Laboratory methane and ammonia measurements (band and k-tables)

This page contains links to data arising from my early work in analysing laboratory gaseous transmission spectra.

Srong/Sihra Methane k distribution coefficients

This section contains the methane k distribution data described in the paper:

Irwin, P. G. J., S. B. Calcutt, F. W. Taylor and A. L. Weir, Calculated k distribution coefficients for hydrogen- and self_broadened methane in the range 2000-9500 cm-1 from exponential sum fitting to band-modelled spectra, J.G.R. 101, No E11, pp 26137-26154, 1996.

The standard ASCII files (14.82 MBytes each) are contained in:

• Self-broadened methane
• Hydrogen-broadened methane

Alternatively, files compressed using the UNIX utility gzip, (4.46 MBytes each) are in:

• Gzipped self-broadened methane
• Gzipped hydrogen-broadened methane

The actual band data files used to generate the k-tables listed below. The absorption coefficients are in units of (molecule/cm-2)^1 scaled by 1e20. i.e. if you take the listed numbers and multiply by 1e-20 the resulting coefficients are in units of (molecule/cm-2)^1. Lower state energies are in units of (cm-1).

• Kim Strong's methane band data (110 Kbytes)
• Simon Calcutt's ammonia band data (110 Kbytes)
• Revised band model fits to Kim Strong and Kam Sihra's methane transmissions (153 Kbytes)

Ammonia k distribution coefficients

This section contains a set of ammonia self-broadened k distribution data described in the paper: Irwin, P. G. J., S.B. Calcutt, K. Sihra, F.W. Taylor, A.L. Weir, J. Ballard, and W.B. Johnston, Band parameters and k coefficients for self-broadened ammonia in the range 4000-11000 cm-1, J. Quant. Spectrosc. Radiat. Transfer , 62 , pp 193-204, 1999.

The ASCII file (13.82 MBytes ) is contained in:

• Self-broadened ammonia

Alternatively, a gzipped file (4.3 MBytes ) is in:

• Gzipped self-broadened ammonia

Karkoschka and Tomasko (2010) Revised CH4 coefficients

Here is a table calculated from the new CH4 coefficients of Karkoschka and Tomasko (2010). The data are tabulated from 1-2.5 microns and have been calculated with a FWHM of 0.004 microns for work with UIST spectroscopy.

• Karkoschka CH4 k-table (gzipped)

Here are tables calculated from the new CH4 coefficients of Karkoschka and Tomasko (2010) at the native step and resolution of those published band data, i.e. 5cm-1 step 10cm-1 FWHM from 2000 to 19300 cm-1 and 25cm-1 step and 50cm-1 FWHM from 19300 to 25000cm-1. Note, these data have not yet been fully verified.

• Karkoschka CH4 k-table 2000-19300 cm-1 (gzipped)
• Karkoschka CH4 k-table 19300 - 25000 cm-1 (gzipped)

Here are tables calculated from the new CH4 coefficients of Karkoschka and Tomasko (2010) suitable for VIMS observations of Titan, covering the range 1-5 microns with a step of 0.008 microns and FWHM 0.016 microns.

• Karkoschka VIMS CH4 k-table 1 - 5 microns (gzipped)

WKMC-80K CH4 coefficients

Here are two tables used in Irwin et al. (2012), Icarus 220, 369 - 382, which have been generated from the WKMC-80K methane line data of Campargue, Wang et al. The ktables use the Hartmann et al. (2002) line shape for methane and a CH3D/CH4 ratio of 3.6e-4, determined by de Bergh et al. (1986). We found in our paper that this ratio should actually be revised to 2.9e-4, but I have not rescaled the CH3D lines here. Although the tables cover the range 1.4 - 1.9 microns, the The WKMC-80K linedata actually only cover the 1.26 - 1.71 micron range, so zeroes fill the rest of these tables.

• WKMC-80K 1.4-1.9 microns. Step=0.00015 microns, FWHM=0.00003 microns (gzipped)
• WKMC-80K 1.4-1.9 microns. Step=0.001 microns, FWHM=0.004 microns (gzipped)

If you want a table covering the whole 1.4-1.9 micron range, in the following table I have used the WKMC-80K data from 1.4-1.71 microns and the Karkoschka and Tomasko (2010) data from 1.71-1.9 microns.

• WKMC-80K/K&T2010 1.4-1.9 microns. Step=0.001 microns, FWHM=0.004 microns (gzipped)