ANALYSIS OF THE PROFILE OF THE FUNDAMENTAL INFRARED BAND OF HYDROGEN IN PRESSURE-INDUCED ABSORPTION

Abstract

The pressure-induced fundamental infrared absorption band of hydrogen was measured for a series of pressures in the pure gas and in a H₂–He mixture at 300 °K, 195 °K, and 78 °K, and in H₂–A and H₂–N₂ mixtures at 300 °K. The band profiles were separated by a computational procedure into Q_P and Q_R (overlap) components and Q_Q and S(J) (quadrupole) components using a dispersion line shape modified by the Boltzmann law. The dispersion half-width obtained for the overlap components was about twice as great as for the quadrupole components; both half-widths varied as the square root of the temperature. The S(J) lines in pure hydrogen consisted of single and double transitions, the relative intensities of which were in accordance with the assumption of quadrupole interaction. Ortho–para ratios of 3:1 and 1:1 were used in the experiments; the integrated intensities of the band showed very little dependence on the ortho–para ratio, in disagreement with a previously reported result.