Far infrared collisionhyphen;induced absorption in gaseous methane. II. Determination of the octupole and hexadecapole moments

摘要

The octupole and hexadecapole moments of methane are obtained by comparing the experimental and theoretical zeroth spectral moment and the integrated absorption coefficient of the collisionhyphen;induced far infrared rotationndash;translation spectrum. The data presented in Part I of this series and the theory summarized in this paper give the values OHgr;2/sgr;7= 4.67times;10minus;16erg and Fgr;2/sgr;9= 1.56times;10minus;16erg, from which we obtain the octupole and hexadecapole moments, respectively, Verbar;OHgr;Verbar; = (2.22plusmn;0.12) times;10minus;34esusdot;cm3and Verbar;Fgr;Verbar; = (4.8plusmn;0.5) times;10minus;42esusdot;cm4for sgr;=3.758 Aring;. An argument is advanced as to why it is preferable to report these results in the form OHgr;2/sgr;7and Fgr;2/sgr;9, where sgr; is the molecular diameter parameter appearing in the potential function.