ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
A beam of highly vibrationally excited (v≤20) Li2 molecules has been generated via Franck–Condon pumping using a cw ring dye laser. The linearly polarized light from a second cw dye laser is used to determine the polarization of the remaining unscattered molecules of the beam after it has passed through a scattering cell filled with krypton gas. The dependence of the state selective total integral cross section on orientation is obtained from the anisotropy of the angular momentum distribution of the beam molecules described by 1+a2P2(cos θ), where θ is the angle between the angular momentum vector and the velocity vector. The measured polarization increases from a2=−0.019±0.007 for Li2(v=0)–Kr collisions to a2=−0.074±0.016 for Li2(v=20)–Kr collisions. The measurements are interpreted in a vibrationally adiabatic approximation in terms of the potential anisotropy parameter q2 for an assumed simple anisotropic potential model V=±(Cs/Rs) [1+q2⋅P2(cos γ)], where γ is the angle between bond distance r and distance between center of mass R. For the v=20 vibrationally excited molecules we obtain q2=1.38±0.31 compared to q2=0.47±0.15 for the v=0 molecules. This large increase in anisotropy with vibrational excitation is compared with that obtained from a previously proposed model for Li2(v)–He [J. Chem. Phys. 85, 7062 (1986)].
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.455523
