Version 4.2 (May 2002)

Constants for molecules of astrophysical interest
in the gas phase: photodissociation,
microwave and infrared spectra.

J. Crovisier
Observatoire de Paris, Section de Meudon
F-92195 Meudon, France
Jacques.Crovisier@obspm.fr

1. Introduction.

	This document is a compilation of references for molecular data relevant to radio and infrared observations of molecules, radicals and ions of astrophysical interest. It was started in 1989 within the working group "Laboratory Spectroscopy for ISO" (Encrenaz et al. 1992). It was originally intended for the preparation of observations with ISO, but it may be useful for all kinds of astrophysical observations (from the ground or from space) in the radio and infrared 
domains.

	This compilation includes 245 species, representing all (or almost all) molecules detected at the present time in the interstellar medium, in comets and in planetary atmospheres (except the Earth), as well as several other molecules, not yet detected, but which are believed to be of astrophysical importance (such as those suggested by Turner, 1992). Isotopic species (with the exception of a few deuterated species) are not systematically included. Section 7 gives the list of the molecules.

	The rationale to establish this compilation was first to search in the previous compilations listed below (Sections 3 and 6), then to search in the recent literature for recent works not reported in previous compilations (this second search being still far from complete at the present stage). Thus the references are far from being comprehensive. The idea is to provide the reader with the references to the most recent works, where more comprehensive references can be generally found.

This compilation is given without warranty. It has not been cautiously proof-read. Therefore, the reader who plans to use the data is invited to check them with the original publications. No serious effort of selection within the available data has been made and the quoted works are not guaranteed to be the best ones or the most up-to-date.

Acknowledgements. This work benefited from the support and advices of many colleagues.

2. Availability

This compilation is freely available from the web page at URL :
http://wwwusr.obspm.fr/~crovisie/basemole/
An instruction text file gives instructions on how to recover the files and on their format.

3. Description of the entries for individual molecules.

	The known data for each molecule are summarized in one or two pages in the following way:

- Formula in alphabetical order of the elements, usual formula (in developed form), name (official designation), other name(s) (optional).

- Electronic state of the ground state and symmetry (point group) .

- Photodissociation rates:
	- in the Solar System, at 1 AU from Sun (relevant for cometary or aeronomical studies);
	- in the interstellar medium: we give the rate evaluated by van Dishoeck (1988), assuming the UV radiation field of Mathis et al. (1983, Astron. Astrophys. 128, 212), and that of Roberge et al. (1991).

- Fundamental vibrational modes:
	- numbering;
	- symmetry species;
	- fundamental frequency;
	- band strength measured in the laboratory (generally in units of cm-2 atm-1 at STP); "na" means that the band is not active (dipolar transition not allowed).
	- Einstein A-coefficient of the band;
	- excitation rate (g-factor) of the band by the Sun at 1 AU (relevant for cometary or aeronomical studies);
	- mode assignation;
	- references to vibrational data.
The modes are ordered first into symmetry species, then, within each species, by increasing frequency. An exception is made for linear triatomics, for which, following the tradition, 2 is the bending mode.

- Electronic bands (optional, when such bands occur in the IR range; the frequency cut-off is fixed around 10 000 cm-1).

- Rotational structure and constants:
	- A, B, C constants, dipolar moments;
	- references to rotational structure.

- Astrophysical detections:
	- where this molecule is observed, and which kind of transitions are observed;
	- references to first astrophysical detections (optional).

Uncertain or speculative numerical values (e.g. from ab initio calculations) are given between parentheses.

All references are given with the full titles of the papers so that the reader could have an idea of their contents (when the titles are not explicit enough, further indications are given in italics). General references already listed in Section 6 are only mentioned in abridged form.

Texts in italics are personal comments. X's may replace lacking data.

4. A guided tour to available data bases and compilations.

4.1 Rotational structure and rotational constants.

	The rotational constants and transitions of several molecules (28 plus isotopic species) are reviewed in a series of papers in the J. Phys. Chem. Ref. Data.

	Lovas and Tieman 1974 and Lovas 1978 have compiled the rotational spectral lines observed and reported in the open literature for 83 diatomic and 54 triatomic molecules, respectively, with derived molecular constants.

	Landolt-Börnstein 1982 gives a comprehensive compilation of molecular constants (for molecules and radicals, but not ions) including rotational constants and dipolar moments, but not vibrational constants.

	Lovas 1991 lists all the molecular lines observed in radio astronomy. It may be consulted at the internet address http://physics.nist.gov/PhysRefData/micro/html/intro.html. An extended version of this work in computer readable form ("Spectral Line Atlas for Interstellar Molecules") lists all measured and computed microwave transitions of these molecules, with references; the line strengths and Einstein A-coefficients are given for some of the molecules (to our knowledge, the 1986 version has not been updated).

	Poynter & Pickett (Poynter and Pickett 1984; Pickett, Poynter and Cohen 1991) is the JPL submillimetre, millimetre and microwave spectral line catalogue (aka JPL molecular data base). It lists transitions of 273 atoms and molecules, with isotopic species, in computer readable form. The data result from comprehensive modelling of each molecule. Einstein A-coefficients may be easily obtained from the base. A hard-copy document gives details on the use of the base as well as comprehensive references for each molecule. The last updated version can be obtained by anonymous ftp to ftp.spec.jpl.nasa.gov and may be consulted at the internet address http://spec.jpl.nasa.gov. 

	The Cologne spectroscopy group is currently providing their results in the same format as the JPL molecular data base (Müller et al. 2001; http://www.cdms.de).

	GEISA, HITRAN, and ATMOS (see 3.2) include the rotational transitions of a few molecules.

	MOGADOC is a machine-readable literature compilation on free molecules established for microwave spectroscopy, molecular radio astronomy, and gas-phase electron diffraction, with a special interest on structural formulas and parameters.

4.2 Vibrational structure and vibrational constants.

	Huber and Herzberg 1979 give a comprehensive review with detailed references for diatomic species. Reference updates for this work are compiled by Bernath and McLeod (2001, DiRef project). For polyatomic species, the compilation of Herzberg III (1966) has not been updated. Band strengths are not reported.

	Shimanouchi I and II give a compilation of fundamental vibrational frequencies for 223 and 212 molecules, respectively. Selected values of the frequencies are given, together with observed infrared and Raman spectral data and references to the original literature. The selection of vibrational fundamentals has been based on studies of the spectral data and normal-coordinate analyses.

	Jacox 1984, 1988 & 1990 has achieved a compilation of band centre evaluations for unstable species (radicals and ions). A recent compilation of references to high-resolution spectra of transient molecules is given by Bernath1990.

	Pugh and Rao 1976 give a compilation of vibrational band strengths for 70 molecules (and some isotopic species) of less than 6 atoms. Smith et al. 1985 and Smith et al. 1992 have updated and completed this compilation for 60 species.

	GEISA and HITRAN are two similar data bases (basically using the same origins of information) accessible by computer. They list the microwave and IR transitions of molecules of atmospheric interest (more than 500 000 transitions for 41 species, plus isotopic species, are listed in the last version of GEISA). The line strengths are given, and the Einstein A-coefficients may be retrieved. Information on HITRAN can be obtained at the internet address http://www.hitran.com and a CDROM version is available. ATMOS is a similar data base, with the same sources plus updates, but is not publicly accessible.

	Guelachvili and Rao I & II are compilations of accurate wavenumbers of the vibrational bands of selected species, for wavelength calibration purpose.

	Several atlases of infrared laboratory spectra are commercially available (Sadtler 1972, Aldrich 1989).

4.3 General

	Molecular data are regularly reported in a large variety of international publications. The most important ones are the Journal of Chemical Physics, the Journal of Molecular Spectroscopy , and the Astrophysical Journal.

	The Berkeley Newsletter, published bi-monthly, gives comprehensive references to all new publications concerning the spectroscopy and structure of small molecules.

	A project similar to the present one, in the visible and UV ranges (although in a somewhat different spirit), is presently undertaken by Kim and A'Hearn (1993).

5. Identified problems

	Photodissociation rates are reliably known for most of the common molecules which have well-measured UV absorption spectra in the laboratory. This is not the case for ions and radicals, for which practically nothing is known.

	Rotational data are generally very well-known, due to the development of radio astronomy. Although most data bases do not extend further than the submillimetre region, they could be extrapolated to the far IR, through modelling from known rotational constants. Although such extrapolations may not be accurate enough for heterodyne observations, they should be sufficient for ISO observations.

	Vibrational data are not as well known as rotational data, especially for radical and ions which can be difficultly observed in the laboratory, or for complex molecules which have rich vibrational spectra. For some transient species, the vibrational fundamental frequencies are only know from cold matrix measurements and may significantly differ from vibrational frequencies in the gas phase. At the present time, vibrational band strengths are only known for a very limited number of radicals and ions. However, ab initio calculations are available in some cases for these species.

	Infrared electronic transitions are only known for a few species (Bernath, 1992). A special effort on this topic is necessary, since the strength of electronic transitions is generally much larger than that of vibrational transitions.

	Strengths for vibrational hot bands are generally completely unknown (even for common simple molecules when the lower level is at relatively high energy). This is a problem since these bands may be readily excited through fluorescence in astrophysical conditions.

6. Band intensities, Einstein A-coefficients and dipolar moments

	Although the basic parameter for the computation of line intensities is the Einstein coefficient for spontaneous emission A, this parameter is rarely directly given in the literature.

	In the literature of infrared spectroscopic laboratory measurements, a considerable creative effort has been made to use a large variety of units for band and line absorption intensities. This problem was reviewed by Pugh and Rao (1976) and Smith et al. (1992) who gave the conversion formulas for most units (but not for all of them). In the present compilation, the laboratory band strengths are generally converted to cm‑2 atm-1 at STP (except in a few cases where the strength may be given in cm-2 atm-1 at a slightly different  temperature, or at an unknown temperature).

	The Einstein A-coefficient (in s-1) of a vibrational band has a physical meaning: it is the inverse of the life time of the upper level, which does not, in first approximation, depend upon the rotational distribution. It is related to the band intensity S (in cm-2 atm-1 at STP) through:

A = 3.080 x 10-8 2 S Zvib / 

for a fundamental band of frequency  (in cm-1). Zvib is the vibrational partition function; for molecules without internal rotation and bending modes at low frequencies, Zvib is close to 1 at room temperature and may be neglected.  is the degeneracy of the band; bands of symmetry species e, , ... are doubly degenerate; those of species f are triply degenerate.

	In some cases (especially for the results of ab initio calculations), instead of the band intensity S, the dipolar moment of the transition is given (or rather, strictly speaking for a vibrational band, the derivative of the electric dipolar moment with respect to normal coordinate ∂ / ∂q, which has the same unit as ). It is related to A through:

A = 0.313 10-6 [∂ / ∂q ]2 3 / 

(for ∂ / ∂q in debyes).

	Finally, the excitation rate g of a fundamental vibrational band by a blackbody of solid angle  and temperature Tb is:

g =  / 4  A [ exp( h c  / k Tb) -1]-1.

Here, these rates are listed for excitation by the Sun at 1 AU, assuming Tb = 5770 K and  / 4  = 5.42 x 10-6.

7. General references

Aldrich 1989. The Aldrich Library of FT-IR Spectra: Vapor Phase, Vol. 3. C.J. Pouchert, Aldrich Chemical, Milwaukee, WI.

ATMOS. Molecular line parameters for the atmospheric trace molecule spectroscopy experiment. Brown, L.R., Farmer, C.B., Rinsland, C.P., Toth, R.A. 1987. Appl. Optics. 26, 5154-5182. See also http://remus.jpl.nasa.gov/atmos/atmos.html.

Berkeley Newsletter. Analysis of Molecular Spectra. Published by J.G. Phillips, S.P. Davis and D.M. Eakin, University of California, Berkeley.

Bernath, P.F. 1990. High resolution infrared spectroscopy of transient molecules. Ann. Rev. Phys. Chem. 41, 91-122.

Bernath, P.F. 1992. Atomic and molecular data needed for analysis of infrared spectra from ISO and SIRTF. In Atomic and Molecular Data for Space Astronomy, Needs, Analysis and Availability. Edts P.L. Smith and W.L. Wiese, Springer Verlag, p. 69-83.

Bernath, P.F., McLeod, S. 2001. DiRef, a database of references associated with the spectra of diatomic molecules. J. Mol. Spec.  207, 287.
	http://diref.uwaterloo.ca

Cologne. Müller, H.S.P., Thorwirth, S., Roth, D.A., Winnewisser, G. 2001. The Cologne Data Base for Molecular Spectroscopy, CDMS. Astron. Astrophys. 370, L49-L52.
	http://www.cdms.de

Encrenaz, T., Crovisier, J., d'Hendecourt, L., Lamy, P., Tully, J.A. 1992. Laboratory spectroscopy for ISO. Report of the ISO working group. In Infrared Astronomy with ISO.Edts T. Encrenaz and M.F. Kessler. Nova Science Publishers, p. 141-158.

GEISA. Gestion et étude des informations spectroscopiques atmosphériques. Jacquinet-Husson, N., Arié, E., Ballard, J., Barbe, A., Bjoraker, G., Bonnet, B., Brown, R., Camy-Peyret, C., Champion, J.P., Chédin, A., Chursin, A., Clerbaux, C., Duxbury, G., Flaud, J.M., Fourrié, N., Fayt, A., Graner, G., Gamache, R., Goldman, A., Golovko, Vl., Guelachvilli, G., Hartmann, J.M., Hilico, J.C., Hillman, J., Lefèvre, G., Lellouch, E., Mikhaïlenko, S.N., Naumenko, O.V., Nemtchinov, V., Newnham, D.A., Nikitin, A., Orphal, J., Perrin, A., Reuter, D.C., Rinsland, C.P.,L.Rosenmann, L., Rothman, L.S., Scott, N.A., Selby, J., Sinitsa, L.N., Sirota, J.M., Smith, A.M., Smith, K.M., Tyuterev, Vl.G., Tipping, R.H., Urban, S.,Varanasi, P., and Weber, M.  1999.  The 1997 spectroscopic GEISA databank. J. Quant. Spect. Rad. Transfer, 62, 205--254. See also http://www.ara.polytechnique.fr/alexei_index.html.

Guelachvili and Rao I. Guelachvili, G., Rao,  K.N. 1986. Handbook of Infrared Standards I. Academic Press, Inc.

Guelachvili and Rao II. Guelachvili, G., Rao,  K.N. 1993. Handbook of Infrared Standards II. With Spectral Coverage of 1.4 m-4 m and 6.2 m-7.7 m. Academic Press, Inc.

Herzberg I. Herzberg, G. 1950. Molecular Spectra and Molecular Structure.I. Spectra of Diatomic Molecules. Van Nostrand Reinhold Comp., New York. (Reedition 1989, Krieger Publ. Comp., Malabar, Florida.)

Herzberg II. Herzberg, G. 1945. Molecular Spectra and Molecular Structure.II. Infrared and Raman Spectra of Polyatomic Molecules. Van Nostrand Reinhold Comp., New York. (Reedition 1991, Krieger Publ. Comp., Malabar, Florida.)

Herzberg III. Herzberg, G. 1966. Molecular Spectra and Molecular Structure. III. Electronic Spectra and Electronic Structure of Polyatomic Molecules. Van Nostrand Reinhold Comp., New York. (Reedition 1991, Krieger Publ. Comp., Malabar, Florida.)

HITRAN High-resolution transmission molecular absorption database (previously known as: AFGL Airforce Geophysics Laboratory atmospheric absorption line parameters compilation). Rothman, L.S., Rinsland, C.P., Goldman, A., Massie, S.T., Edwards, D.P., Flaud, J.-M., Perrin, A., Camy-Peyret, C., Dana, V., Mandin, J.-Y., Schroeder, J., McCann, A., Gamache, R.R., Wattson, R.B., Yoshino, K., Chance, K.V., Jucks, K.W., Brown, L.R., Nemtchinov, V., Varanasi, P. 1998. The HITRAN molecular spectroscopic database and HAWKS (HITRAN atmospheric workstation): 1996 edition. J. Quant. Spect. Rad. Trans. 60, 665-710. Also http://www.hitran.com.

Huber, K.P., Herzberg, G. 1979. Molecular Spectra and Molecular Structure. IV. Constants of Diatomic molecules. Van Nostrand Reinhold Comp., New York.
	http://webbook.nist.gov/chemistry/

Huebner, W.F., Keady, J.J., Lyon, S.P. 1992. Solar photorates for planetary atmospheres and atmospheric pollutants. Astrophys. Space Science 195, 1-294. Also: 
	http://www.space.swri.edu/amop/

Jacox, M.E. 1984. Ground-state vibrational energy levels of polyatomic transient molecules. J. Phys.Chem. Ref. Data 13, 945.

Jacox, M.E. 1988. Electronic energy levels of small polyatomic transient molecules. J. Phys.Chem. Ref. Data 17, 269-511.

Jacox, M.E. 1990. Vibrational and electronic energy levels of polyatomic transient molecules. Supplement 1. J. Phys.Chem. Ref. Data 19, 1387-1546.

Kim, S.A., A'Hearn, M.F. 1993. UV and visible line atlas (UVLA) for atoms and molecules in the atmospheres of planets and comets. Project.

Landolt-Börnstein. 1982. Numerical Data and Functional Relationships in Science and Technology. Edt. K.-H. Hellwege. Group II: Atomic and Molecular Physics. Vol. 14: Molecular constants, mostly from microwave, molecular beam, and electron resonance spectroscopy. Springer Verlag, Berlin.

Lovas, F.J. 1978. Microwave spectral tables II. Triatomic molecules. J. Phys. Chem. Ref. Data 7, 1445‑1750.

Lovas, F.J. 1992. Recommended rest frequencies for observed interstellar molecular microwave transitions - 1991 revision. J. Phys. Chem. Ref. Data 21, 181-272. Also:  http://physics.nist.gov/restfreq.

Lovas, F.J., Suenram, R.D. 1989. Microwave spectral tables. III. Hydrocarbons, CH to C10H10. J. Phys. Chem. Ref. Data 18, 1245.

Lovas, F.J., Tieman, E. 1974. Microwave spectral tables I. Diatomic molecules. J. Phys. Chem. Ref. Data 3, 609-761.

MOGADOC Molecular Gas-Phase Documentation. Vogt, J. 1992. MOGADOC: a bibliographic numerical resource for gas phase molecular spectroscopy and structure. J. Mol. Spect. 155, 413-416. Vogt, J., Mez-Stark, B., Vogt, N., Hutter, W. 1999. MOGADOC — a data base for gasphase molecular spectroscopy and structure. J. Mol. Struct. 485-486, 249-256 Also: http://www.uni-ulm.de/strudo/mogadoc/

Pickett H.M., Poynter, R.L., Cohen, E.A., Delitsky, M.L., Pearson, J.C., Müller, H.S.P. 1998. Submillimeter, millimeter and microwave spectral line catalogue.   J. Quant. Spectrosc. Radiat. Transfer 60, 883-890.  Also: http://spec.jpl.nasa.gov

Poynter R.L., Pickett H.M. 1984. Submillimeter, millimeter and microwave spectral line catalogue. JPL publication 80-23, revision 2. Also: magnetic tape version (1991). See also ibid. 1985, Appl. Opt. 24, 2235.

Pugh, L.A., Rao, K.N. 1976. Intensities from infrared spectra. In Molecular spectroscopy: Modern research, Edt. K.N. Rao, Academic Press, Vol. II p.165.

Roberge, W.G., Jones, D., Leep, S., Dalgarno, A. 1991. Interstellar photodissociation and photoionization rates. Astrophys. J. Supl. Series 77, 287-297.

Sadtler 1972. Sadtler Reference Spectra - Gases & Vapors High Resolution Infrared. Philadelphia: Sadtler Research Laboratories, Inc.

Shimanouchi I. Tables of molecular vibrational frequencies. Consolidated volume I. Shimanouchi, T. 1972. Nat. Stand. Ref. Data Series 39, 1-160.

Shimanouchi II. Tables of molecular vibrational frequencies. Consolidated volume II. Shimanouchi, T. 1977. J. Phys. Chem. Ref. Data 6, 993-1102.

Smith, M.A.H., Rinsland, C.P., Fridovich, B., Rao, K.N. 1985. Intensities and collision broadening parameters from infrared spectra. In Molecular spectroscopy: Modern research, Edt. K.N. Rao, Academic Press, Vol. III p.111.

Smith, M.A.H., Rinsland, C.P., Devi, V.M., Rothman, L.S., Rao, K.N. 1992. Intensities and collision-broadening parameters from infrared spectra: an update. In Spectroscopy of the Earth's Atmosphere and Interstellar Medium, Edts K.N. Rao and A; Weber, Academic Press, p. 153-260.

Turner, B.E. 1992. What species remain to be seen ? In Astrochemistry of Cosmic Phenomena, IAU Symp. No 150, Edt. P.D. Singh, Kluwer Academic Publ., p. 181-192.

van Dishoeck, E.F. 1988. Photodissociation and photoionization processes. In Rate Coefficients in Astrochemistry, Edts T.J. Millar and D.A. Williams, Kluwer Academic Publ., p. 49.

8. Index

This index follows the order in which the molecules are organized in the compilation. Molecules are divided into two groups: (a) those containing no carbon atoms, which are arranged with the elemental symbols of the empirical formulas in alphabetical order and are listed alphabetically, and in ascending order of the empirical formula subscripts; (b) molecules containing carbon, which are ordered in the same way except that carbon is listed first and hydrogen second. Deuterated species are listed after the corresponding main isotopic species.

Species not containing carbon

AlCl	AlCl	Aluminium Chloride	1
AlF	AlF	Aluminium Fluoride	2
AlH	AlH	Aluminium Hydride	3
AlHO	AlOH		4
AlO	AlO	Aluminium Monoxide	5
AsH3	AsH3	Arsine	6
BrH	HBr	Hydrogen Bromide	7
CaH	CaH	Calcium Hydride	8
CaHO	CaOH	Calcium Hydroxide	9
CaO	CaO	Calcium Monoxide	10
CaS	CaS	Calcium Suphide	11
ClH	HCl	Hydrogen Chloride	12
ClHO	HOCl	Hypochlorous Acid	13
ClK	KCl	Potassium Chloride	14
ClNa	NaCl	Sodium Chloride	15
ClO	ClO	Chlorine Monoxide	16
FH	HF	Hydrogen Fluoride	17
FeO	FeO	Iron Monoxide	18
FeS	FeS	Iron Sulphide	19
GeH4	GeH4	Germane	20
HI	HI	Hydrogen Iodide	21
HK	KH	Potassium Hydride	22
HLi	LiH	Lithium Hydride	23
HMg	MgH	 Magnesium Hydride	24
HMg+	MgH+	Magnesium Hydride Ion	25
HMgO	MgOH	Magnesium Hydroxide	26
HN	NH	Nitrogen Hydride	27
HN+	NH+	Nitrogen Hydride Ion	28
HNO	HNO	Nitroxyl	29
HNSi	HNSi	Iminosilicon	30
HN2+	N2H+	Protonated Nitrogen	31
HNa	NaH	Sodium Hydride	32
HNaO	NaOH	Sodium Hydroxide	33
HO	OH	Hydroxyl Radical	34
d-HO	OD	d-Hydroxyl Radical	36
HO+	OH+	Hydroxyl Ion	37
HOP	HPO		38
HOSi+	HOSi+		39
HO2	HO2	Hydroperoxyl Radical	40
HP	PH	Phosphorus Hydride	41
HS	SH	Sulphur Hydride	42
HS+	SH+	Sulphur Hydride Ion	43
HSi	SiH	Silicon Hydride	44
H2	H2	Dihydrogen	45
d-H2	HD		46
H2N	NH2	Aminyl Radical	47
H2N2	N2H2	Diazine	48
H2O	H2O	Water	49
d-H2O	HDO	d-Water	51
H2O+	H2O+	Water Ion	52
H2O2	H2O2	Hydrogen Peroxide	53
H2S	H2S	Hydrogen Sulphide	54
H2Se	H2Se	Hydrogen Selenide	56
H2Si	SiH2	Silylene	57
H3+	H3+	Protonated Dihydrogen	58
d-H3+	H2D+		59
H3N	NH3	Ammonia	60
d-H3N	NH2D	d-Ammonia	62
H3O+	H3O+	Hydronium Ion	63
H3P	PH3	Phosphine	65
H4N+	NH4+	Ammonium Ion	66
H4N2	NH2NH2	Hydrazine	67
H4Si	SiH4	Silane	68
MgO	MgO	Magnesium Monoxide	69
MgS	MgS	Magnesium Sulphide	70
NO	NO	Nitric Oxide	71
NO+	NO+	Nitric Oxide Ion	72
NO2	NO2	Nitrogen Dioxide	73
NP	PN	Phosphorus Nitride	74
NS	NS	Nitrogen Sulphide	75
NSi	SiN	Silicon Nitride	76
N2	N2	Molecular Nitrogen	77
N2+	N2+	Dinitrogen Ion	78
N2O	N2O	Nitrous Oxide	79
NaO	NaO	Sodium Monoxide	80
OP	PO	Phosphorus Monoxide	81
OS	SO	Sulphur Monoxide	82
OS+	SO+	Sulphur Monoxide Ion	83
OSi	SiO	Silicon Monoxide	84
OSi+	SiO+	Silicon Monoxide Ion	85
OTi	TiO	Titanium Monoxide	86
O2	O2	Molecular Oxygen	87
O2S	SO2	Sulphur Dioxide	88
O3	O3	Ozone	89
PS	PS	Phosphorus Sulphide	90
SSi	SiS	Silicon Sulphide	91
S2	S2	Diatomic Sulphur	92

Species containing carbon

CAlN	AlNC	Alumiium Isocyanide	93
CCl	CCl	Carbon Monochloride	94
CMgN	MgNC	Magnesium Isocyanide	95
CMgN	MgCN	Magnesium Cyanide	96
CN	CN	Cyanogen Radical	97
CN+	CN+	Cyanogen Ion	99
CNNa	NaCN	Sodium Cyanide	100
CNO	NCO	NCO Radical	101
CNSi	SiCN		102
CNSi	SiNC		103
CN2	NCN		104
CO	CO	Carbon Monoxide	105
CO+	CO+	Carbon Monoxide Ion	107
COS	OCS	Carbonyl Sulphide	108
CO2	CO2	Carbon Dioxide	109
CO2+	CO2+	Carbon Dioxide Ion	110
CP	CP	CP Radical	111
CS	CS	Carbon Monosulphide	112
CS+	CS+	Carbon Monosulphide Ion	113
CS2	CS2	Carbon Disulphide	114
CSi	SiC	SiC Radical	115
CH	CH	Methyladyne Radical	116
CH+	CH+	Methylidyne Ion	118
CHN	HCN	Hydrogen Cyanide	119
CHN	HNC	Hydrogen Isocyanide	121
CHNO	HNCO	Isocyanic Acid	122
CHNO	HOCN	Cyanic Acid	123
CHNO	HCNO	Fulminic Acid	124
CHNS	HNCS	Thioisocyanic Acid	125
CHO	HCO	Formyl Radical	126
CHO+	HCO+	Formyl Ion	127
CHO+	HOC+	Hydroxymethylidynium	128
CHO2	HOCO	Hydroxyformyl Radical	129
CHO2+	HOCO+	Protonated Carbon Dioxyde	130
CHOS+	HOCS+		131
CHP	HCP	Methinophosphide	132
CHS+	HCS+	Thioformyl Ion	133
CH2	CH2	Methylene Radical	134
CH2+	CH2+		135
CH2N	H2CN	Methylene Amidogen	136
CH2N+	HCNH+	Protonated Hydrogen Cyanide	137
CH2N2	NH2CN	Cyanamide	138
CH2O	H2CO	Formaldehyde	139
CH2O2	HCOOH	Formic Acid	141
CH2S	H2CS	Thioformaldehyde	143
CH3	CH3	Methyl Radical	144
CH3+	CH3+		145
CH3N	CH2NH	Methanimine	146
CH3NO	NH2HCO	Formamide	147
CH3O	CH3O	Methoxy Radical	148
CH3O+	H2COH+	Protonated Formaldehyde	149
CH3P	CH2PH	Methilenephosphine	150
CH4	CH4	Methane	151
d-CH4	CH3D	d-Methane	152
CH4N2O	(NH2)2CO	Urea	153
CH4O	CH3OH	Methanol	154
CH4S	CH3SH	Methyl Mercaptan	156
CH5N	CH3NH2	Methylamine	157
C2	C2	Dicarbide	159
C2Mg	MgC2		160
C2N	C2N		161
C2N2	C2N2	Dicyanogen	162
C2O	C2O	Dicarbon Monoxide	163
C2S	C2S	C2S Radical	164
C2Si	c-SiC2	Silicon Dicarbide	165
C2H	C2H	Ethynyl Radical	166
C2HMg	MgCCH	Magnesium Acetylide	168
C2HN	HCCN		169
C2HNa	NaCCH	Sodium Acetylide	170
C2HSi	HSiC2		171
C2HSi	SiCCH		172
C2H2	CHCH	Acetylene	173
C2H2N	CH2CN	Cyanomethyl Radical	174
C2H2O	H2CCO	Ketene	175
C2H2S	H2C2S	Thioketene	176
C2H3	CH2CH	Vinyl Radical	177
C2H3+	C2H3+	Protonated Acetylene	178
C2H3N	CH3CN	Methyl Cyanide	179
C2H3N	CH3NC	Methyl Isocyanide	181
C2H3P	CH3CP	Ethylidynephosphine	182
C2H4	CH2CH2	Ethylene	183
C2H4O	CH3CHO	Acetaldehyde	185
C2H4O	CH2CHOH	Vinyl Alcohol	187
C2H4O	c-C2H4O	Ethylene Oxide	188
C2H4O2	HCOOCH3	Methyl Formate	189
C2H4O2	CH3COOH	Acetic Acid	191
C2H4O2	CH2OHCHO	Glycolaldehyde	193
C2H5NO2	NH2CH2COOH	Glycine	194
C2H6	CH3CH3	Ethane	195
C2H6O	CH3CH2OH	Ethanol	196
C2H6O	CH3OCH3	Dimethyl Ether	198
C3	C3	C3 Radical	200
C3N	C3N	Cyanoethynyl Radical	202
C3O	C3O	Tricarbon Monoxide	203
C3O2	OC3O	Carbon Suboxide	204
C3S	C3S	C3S Radical	205
C3Si	SiC3		206
C3Si	c-SiC3		207
C3H	C3H	Propynyl Radical	208
C3H	c-C3H	Cyclic Propynyl Radical	209
C3HN	HC3N	Cyanoacetylene	210
C3HN	HCCNC	Isocyanoacetylene	212
C3HN	HNCCC		213
C3HP	HC3P	Phosphabutadiyne	214
C3H2	H2CCC	Propadienylidene	215
C3H2	c-C3H2	Cyclopropenylidene	216
C3H2+	C3H2+		218
C3H2N+	HC3NH+	Protonated Cyanoacetylene	219
C3H2O	HC2CHO	Propynal	220
C3H3N	CH2CHCN	Vinyl Cyanide	221
C3H3+	C3H3+		222
C3H4	CH3CCH	Propyne	223
C3H4	CH2CCH2	Allene	225
C3H5N	CH3CH2CN	Ethyl Cyanide	226
C3H6	c-C3H6	Cyclopropane	227
C3H6	CH3CHCH2	Propylene	228
C3H6O	CH3COCH3	Acetone	229
C3H6O3	(H2CO)3	Trioxane	231
C3H8	CH3CH2CH3	Propane	232
C4	C4	C4 Radical	233
C4N2	C4N2	Dicyanoacetylene	234
C4O	C4O	Tetracarbon Monoxide	235
C4Si	SiC4		236
C4H	C4H	Butadiynyl Radical	237
C4H2	HCCCCH	Diacetylene	238
C4H2	H2CCCC	Butatrienylidene	239
C4H3N	CH3C3N	Methylcyanoacetylene	240
C4H5N 	CH2CHCH2CN	Allyl Cyanide	241
C4H5N	CH3(CH)2CN	Crotonitrile	242
C4H5N	CH2CCH3CN	Methacrylonitrile	243
C5	C5	C5 Radical	244
C5N	C5N	Cyanobutadiynyl Radical	245
C5O	C5O	Pentacarbon Monoxide	246
C5S	C5S		247
C5H	C5H	Pentynylidyne Radical	248
C5HN	HC5N	Cyanobutadiyne	249
C5H2	C5H2	Pentatetraenylidene	250
C5H4	CH3C4H	Methyldiacetylene	251
C6	C6	C6 Radical	252
C6H	C6H	Hexatriynyl Radical	253
C6H2	HC6H	Triacetylene	254
C6H2	C6H2	Hexapentaenylidene	255
C6H3N	CH3C5N	Hexa-2,4-diynenitrile	256
C6H6	C6H6	Benzene	257
C7	C7	C7 Radical	259
C7H	C7H	 Heptatriynylidyne	260
C7HN	HC7N	Cyanohexatriyne	261
C8	C8	C8 Radical	262
C8H	C8H	 Octatetraynyl	263
C9	C9	C9 Radical	264
C9H	C9H	 Nonatetraynylidyne	265
C9HN	HC9N	Cyanooctatetrayne	266
C10H	C10H	 Decapentaynyl	267
C11H	C11H	 	268
C11HN	HC11N	Cyanodecapentayne	269
C13HN	HC13N		270
C15HN	HC15N		271
C17HN	HC17N		272

9. Thematic index

The molecules included in the compilation are grouped here into families. Note that a given molecule may appear in different families, or may not be refered at all.

Hydrides

AlH	AlH	aluminium hydride	
BrH	HBr	hydrogen bromide
CaH	CaH	calcium hydride	
ClH	HCl	hydrogen chloride	
FH	HF	hydrogen fluoride	
HI	HI	Hydrogen Iodide
HK	KH	Potassium Hydride
HLi	LiH	Lithium Hydride
HMg	MgH	magnesium hydride	
HMg+	MgH+	magnesium hydride ion	
HN	NH	nitrogen hydride	
HN+	NH+	nitrogen hydride ion	
HNa	NaH	sodium hydride	
HO	OH	hydroxyl radical	
d-HO	OD	d-hydroxyl radical	
HO+	OH+	hydroxyl ion	
HP	PH	phosphorus hydride	
HS	SH	sulfur hydride	
HS+	SH+	sulfur hydride ion	
HSi	SiH	silicon hydride		
CH	CH	methylidyne radical	
CH+	CH+	methylidyne ion	

Chlorine compounds

ClH	HCl	hydrogen chloride	
ClHO	HOCl	hypochlorous acid	
ClK	KCl	potassium chloride	
ClNa	NaCl	sodium chloride	
ClO	ClO	chlorine monoxide	
CCl 	CCl	carbon monochloride	

Sulfur compounds

CaS	CaS	calcium sulfide	
FeS	FeS	iron sulfide
HS	SH	sulfur hydride	
HS+	SH+	sulfur hydride ion	
H2S	H2S	hydrogen sulfide	
MgS	MgS	magnesium sulfide	
NS	NS	nitrogen sulfide	
OS	SO	sulfur monoxide	
OS+	SO+	sulfur monoxide ion	
O2S	SO2	sulfur dioxide	
PS	PS	phosphorus sulfide	
SSi	SiS	silicon sulfide		
S2	S2	diatomic sulfur	
COS	OCS	carbonyl sulfide	
CS	CS	carbon monosulfide	
CS+	CS+	carbon monosulfide ion	
CS2	CS2	carbon disulfide	
CHNS	HNCS	thioisocyanic acid	
CHOS+	HOCS+
CHS+	HCS+	thioformyl ion	
CH2S	H2CS	thioformaldehyde	
CH4S	CH3SH	methyl mercaptan	
C2S	C2S	C2S radical	
C2H2S	H2C2S	thioketene	
C3S	C3S	C3S radical
C5S	C5S	

Phophorous compounds

HOP	HPO		
HP	PH	phosphorus hydride	
H3P	PH3	phosphine	
NP	PN	phosphorus nitride	
OP	PO	phosphorus monoxide	
PS	PS	phosphorus sulfide	
CP	CP	CP radical	
CHP	HCP	methinophosphide	
CH3P	CH2PH	methilene phosphine	
C2H3P	CH3CP	ethylidyne phosphine	
C3HP	HC3P	phosphabutadiyne	

Silicon compounds

HNSi	HNSi	Iminosilicon
HOSi+	HOSi+		
HSi	SiH	silicon hydride		
H2Si	SiH2	silylene
H4Si	SiH4	silane			
NSi	SiN	silicon nitride		
OSi	SiO	silicon monoxide
OSi+	SiO+	silicon monoxide ion	
SSi	SiS	silicon sulfide		
CNSi	SiCN			
CNSi	SiNC			
CSi	SiC	SiC radical			
C2Si 	c-SiC2	silicon dicarbide	
C2HSi	HSiC2				
C2HSi	SiCCH
C3SI	C3Si	
C3Si	c-C3Si	
C4Si	SiC4				

Magnesium compounds

HMg	MgH	Magnesium Hydride	
HMg+	MgH+	Magnesium Hydride Ion	
HMgO	MgOH	Magnesium Hydroxide	
MgO	MgO	Magnesium Monoxide	
MgS	MgS	Magnesium Sulphide	
CMgN	MgNC	Magnesium Isocyanide	
CMgN	MgCN	Magnesium Cyanide	
C2Mg	MgC2	
C2HMg	MgC2H	Magnesium Acetylide	

Water group

HO	OH	hydroxyl radical	
d-HO	OD	d-hydroxyl radical	
HO+	OH+	hydroxyl ion	
HO2	HO2	hydroperoxyl radical	
H2O	H2O	water	
d-H2O	HDO	d-water	
H2O+	H2O+	water ion	
H2O2	H2O2	hydrogen peroxide	
H3O+	H3O+	hydronium ion	

Carbon oxides and their ions

CO	CO	carbon monoxide	
CO+	CO+	carbon monoxide ion	
CO2	CO2	carbon dioxide	
CO2+	CO2+	carbon dioxide ion	
C2O	C2O	dicarbon monoxide
C3O	C3O	tricarbon monoxide	
C3O2	OC3O	carbon suboxide	
C4O	C4O	tetracarbon monoxide
C5O	C5O	pentacarbon monoxide

Hydrocarbons and related radicals and ions

CH	CH	methylidyne radical	
CH+	CH+	methylidyne ion	
CH2	CH2	methylene radical	
CH2+	CH2+		
CH3	CH3	methyl radical	
CH3+	CH3+		
CH4	CH4	methane	
d-CH4	CH3D	d-methane	
C2H	C2H	ethynyl radical	
C2H2	CHCH	acetylene	
C2H3	CH2CH	vinyl radical
C2H3+	C2H3+	protonated acetylene
C2H4	CH2CH2	ethylene	
C2H6	CH3CH3	ethane	
C3H	C3H	propynyl radical	
C3H	c-C3H	cyclic propynyl radical	
C3H2	H2CCC	propadienylidene	
C3H2	c-C3H2	cyclopropenylidene	
C3H2+	C3H2+	
C3H3+	C3H3+	
C3H4	CH3CCH	propyne	
C3H4	CH2CCH2	allene	
C3H6	c-C3H6	cyclopropane
C3H6	CH3CHCH2	propylene
C3H8	CH3CH2CH3	propane	
C4H	C4H	butadiynyl radical	
C4H2	HCCCCH	diacetylene	
C4H2	H2CCCC	butatrienylidine	
C5H	C5H	pentynylidyne radical	
C5H2	C5H2	radical	
C5H4	CH3C4H	methyl diacetylene	
C6H	C6H	hexatriynyl radical	
C6H2	HC6H	triacetylene
C6H2	C6H2	Hexapentaenylidene	
C6H6	C6H6	benzene
C7H	C7H	radical
C8H	C8H	radical
C9H	C9H	radical
C11H	C11H	radical	

CHN species

CHN	HCN	hydrogen cyanide	
CHN	HNC	hydrogen isocyanide	
CH2N	CH2N	methylene amidogen
CH2N+	HCNH+	protonated hydrogen cyanide
CH2N2	NH2CN	cyanamide	
CH3N	CH2NH	methanimine	
CH5N	CH3NH2	methylamine	
C2HN	HC2N		
C2H2N	CH2CN	cyanomethyl radical	
C2H3N	CH3CN	methyl cyanide	
C2H3N	CH3NC	methyl isocyanide	
C3HN	HC3N	cyanoacetylene
C3HN	HCCNC	isocyanoacetylene	
C3HN	HNCCC		
C3H2N+	HC3NH+	protonated cyanoacetylene
C3H3N	CH2CHCN	vinyl cyanide	
C3H5N	CH3CH2CN	ethyl cyanide	
C4H3N	CH3C3N	methylcyanoacetylene	
C4H5N	CH2CHCH2CN	allyl cyanide	
C4H5N	CH3(CH)2CN	crotonitrile	
C4H5N	CH2CCH3CN	methacrylonitrile	
C5HN	HC5N	cyanobutadiyne	
C6H3N	CH3C5N	hexa-2,4-diynenitrile	
C7HN	HC7N	cyanohexatriyne	
C9HN	HC9N	cyanooctatetrayne	
C11HN	HC11N	cyanodecapentayne	
C13HN	HC13N		
C15HN	HC15N		
C17HN	HC17N		

CHO species

CHO	COH	formyl radical	
CHO+	HCO+	formyl ion	
CHO+	HOC+	hydroxymethylidynium
CHO2	HOCO	hydroxyformyl Radical	
CHO2+	HOCO+	protonated carbon dioxide	
CH2O	H2CO	formaldehyde	
CH2O2	HCOOH	formic acid	
CH3O	CH3O	methoxy radical
CH3O+	H2COH+	protonated formaldehyde	
CH4O	CH3OH	methanol	
C2H2O	H2CCO	ketene	
C2H4O	CH3CHO	acetaldehyde	
C2H4O	CH2CHOH	vinyl alcohol	
C2H4O	c-C2H4O	Ethylene Oxide	
C2H4O2	HCOOCH3	methyl formate
C2H4O2	CH3COOH	acetic acid
C2H5O2	CH2OHCHO	glycolaldehyde	
C2H6O	CH3CH2OH	ethanol	
C2H6O	CH3OCH3	dimethyl ether	
C3H2O	HC2CHO	propynal
C3H6O2	(H2CO)3	trioxane	
C3H6O	CH3COCH3	acetone	

Ions

HMg+	MgH+	magnesium hydride ion	
HN+	NH+	nitrogen hydride ion	
HN2+	N2H+	protonated nitrogen	
HO+	OH+	hydroxyl ion	
HOSi+	HOSi+		
HS+	SH+	sulfur hydride ion	
H2O+	H2O+	water ion	
H3+	H3+	protonated dihydrogen	
d-H3+	H2D+		
H3O+	H3O+	hydronium ion	
H4N+	NH4+	ammonium ion	
NO+	NO+	nitric oxide ion	
N2+	N2+	dinitrogen ion	
OS+	SO+	sulfur monoxide ion	
CN+	CN+	cyanogen ion	
CO+	CO+	carbon monoxide ion	
CO2+	CO2+	carbon dioxide ion	
CS+	CS+	carbon monosulfide ion	
CH+	CH+	methylidyne ion	
CHO+	HCO+	formyl ion	
CHO+	HOC+		
CHO2+	HOCO+	protonated carbon dioxide	
CHOS+	HOCS+
CHS+	HCS+	thioformyl ion	
CH2+	CH2+		
CH2N+	HCNH+	protonated hydrogen cyanide
CH3+	CH3+	
C2H3+	C2H3+	protonated acetylene
C3H2+	C3H2+	
C3H2N+	HC3NH+	protonated cyanoacetylene
C3H3+	C3H3+