HITRAN

The HITRAN format is the format defined by the High-resolution Transmission Molecular Absorption (HITRAN) database . It has been widely adopted by the community of spectroscopists and modellers using spectrospcopic data.

Data are stored in a standardised way in formatted ASCII text files. HITRAN conventions are described on the HITRAN Database Web Site under Section "HITRAN Facts".

We have reproduced some of the tables available at the HITRAN site below for convenience.

• Tables 1 & 2 display all fields included in one record (one line) of a HITRAN data file. Each table corresponds to a version of the HITRAN database (prior-to or after 2000).
• Table 3 lists molecule numbers and formulæ. Isotope numbers can be found on the HITRAN Web site.
• Table 4 displays the error codes and their meanings.

Table 1. Format for HITRAN Parameters, Editions 1986 through 2000 – One record includes 16 parameters and is 100 characters long
Parameter	Molecule number	Isotope number	Transition frequency [cm -1]	Line intensity	|R| 2	Air- broadened width	Self- broadened width	Lower- state energy	Temperature dependence (of air width)	Pressure shift	Upper vibrational quanta	Lower vibrational quanta	Upper local quanta	Lower local quanta	Error code	Reference code
Field length	2	1	12	10	10	5	5	10	4	8	3	3	9	9	3	6




Table 2. New Format for HITRAN Parameters, Editions after 2000 – One record includes 19 parameters and is 160 characters long
Parameter	Molecule number	Isotope number	Transition frequency [cm -1]	Line intensity	Einstein-A coefficient	Air- broadened width	Self- broadened width	Lower- state energy	Temperature dependence (of air width)	Pressure shift	Upper vibrational quanta	Lower vibrational quanta	Upper local quanta	Lower local quanta	Error code	Reference code	Flag for line mixing	Upper statistical weight	Lower statistical weight
Field length	2	1	12	10	10	5	5	10	4	8	15	15	15	15	6	12	1	7	7
FORTRAN descriptor	i2	i1	f12.6	1pe10.3	e10.3	0pf5.4	f5.4	1pf10.4	0pf4.2	f8.6	a15	a15	a15	a15	6i1	6i2	a1	i7	i7




Table 3. HITRAN molecule numbers
#	Molecule		#	Molecule		#	Molecule		#	Molecule		#	Molecule
1	H 2O		9	SO 2		17	HI		25	H 2O2		33	HO 2
2	CO 2		10	NO 2		18	ClO		26	C 2H2		34	O
3	O 3		11	NH 3		19	OCS		27	C 2H6		35	ClONO 2
4	N 2O		12	HNO 3		20	H 2CO		28	PH 3		36	NO +
5	CO		13	OH		21	HOCl		29	COF 2		37	HOBr
6	CH 4		14	HF		22	N 2		30	SF 6		38	C 2H4
7	O 2		15	HCl		23	HCN		31	H 2S
8	NO		16	HBr		24	CH 3Cl		32	HCOOH




Table 4. HITRAN one-digit error codes
Wavenumber [cm -1]			Intensity, Halfwidths, Temperature dependence, Pressure shift
Code	Error range		Code	Error range
0	> 1 cm -1 or unreported		0	Unreported or unavailable
1	Between 1 and 0.1 cm -1		1	Default or constant
2	Between 0.1 and 0.01 cm -1		2	Average or estimate
3	Between 0.01 and 0.001 cm -1		3	> 20%
4	Between 0.001 and 0.0001 cm -1		4	Between 10% and 20%
5	Between 0.0001 and 0.00001 cm -1		5	Between 5% and 10%
6	Better than 0.00001 cm -1		6	Between 2% and 5%
			7	Between 1% and 2%
			8	< 1%