A study of the pressure-induced fundamental rotation-vibration band of deuterium in deuterium-foreign gas mixtures at room temperature

Abstract

The pressure-induced fundamental infrared absorption band of deuterium has been studied in D₂-He, D₂-A and D₂-N₂ mixtures for a series of pressures up to 1200 atm at room temperature. The absorption profile of each mixture shows a well-resolved splitting of the Q branch into two components, QP and QR, whose separation was found to increase linearly with the total density of the mixture. The contours of D₂-A and D₂-N₂ mixtures also show fairly well resolved S(2) peak and indications of several other S and 0 peaks of the band, while these are absent in the contours of D₂-He mixtures. Using the theory and the observed line shape, an attempt was made to decompose the observed contours of D₂-A and D₂-N₂ mixtures. The overlap parts of the Q branches for D₂-A and D₂-N₂ mixtures thus obtained were studied together with the observed contours for D₂-He mixtures which were found to consist mainly of the overlap part of the Q branch. -- The integrated absorption coefficient of the band in the mixtures was found to follow an empirical power series in terms of the partial densities of the component gases. From this series the binary and ternary absorption coefficients were determined for each binary mixture. The theory proposed by Van Kranendonk was applied to the coefficient of the individual lines of the 0 and S branches as well as the quadrupole and overlap parts of the Q branch.