Line Parameters of Methane from 2400 to 3200 cm−1

Abstract

A comprehensive list of line parameters of methane have beem compiled in the 2400 to 3200 cm−1 region. Experimental positions and line strengths greater than 3×10−5 cm−2 atm−1 using spectra of 0.01 to 0.02 cm−1 resolution. The data were recorded at Florida State University with a 4-passed grating spectrometer and at the Kitt Peak National Observatory using a Fourier Transform Spectrometer. The spectra were taken with the gas sample at room (298±2K) and cold (down to 160K) temperatures using optical densities that ranged from 0.01 to 150 M-Torr. From these data positions (of single lines not overlapped by other absorptions) were measured to ± 0.0001 cm−1 and line strengths to 5% or better. The positions and strengths of blended lines were less accurately determined. Experimental lower state energies were determined for many of the lines in the 2700 to 3200 cm−1 region using the cold data. These were used extensively to determine the quantum assignments of the observed lines.