Collision induced absorption spectra of the fundamental band of gaseous deuterium: Overlap parameters of D2ndash;D2collision pairs

摘要

The collision induced absorption of the fundamental band of D2in the pure gas was recorded for a number of gas densities up to 60 amagat at 77 and 196 K with a 2 m absorption cell and at 298 K with a 2.1 m absorption cell. Binary and ternary absorption coefficients of the band have been determined from the measured integrated absorption coefficients. An analysis of the absorption profiles was carried out by assuming appropriate line shapes and the halfwidth parameters dgr;dand dgr;cof the shorthyphen;range overlap induced transitions and dgr;qof the longhyphen;range quadrupole induced transitions have been determined. The profile analysis also made it possible to separate the contributions of these two types of transitions to the total intensity of the band. For the D2ndash;D2collision pairs, the overlap parameters lgr; and rgr;, which represent the magnitude and range, respectively, of the overlap induced dipole moment, and mgr;overlap(sgr;), the overlap induced moment at the Lennardhyphen;Jones intermolecular diameter sgr;, have been determined; these are lgr; = 4.0times;10minus;3, rgr; = 0.21thinsp;Aring;, and mgr;overlap(sgr;) = 2.2times;10minus;2ea0and are compared with those of the H2ndash;H2and HDndash;HD pairs derived from earlier work in our laboratory lsqb;S. P. Reddyetal., Phys. Rev. A 15, 975 (1977); S. P. Reddy and R. D. G. Prasad, J. Chem. Phys. 66, 5259 (1977)rsqb;.