Fg. Baglin et al., INTERACTION-INDUCED RAMAN LIGHT-SCATTERING-STUDIES OF CH4 H-2 MIXTURES AS A FUNCTION OF DENSITY/, JOURNAL OF PHYSICAL CHEMISTRY B, 101(43), 1997, pp. 8816-8822
We have recently interrogated several binary supracritical mixtures by
means of interaction-induced Raman light scattering originating from
a probe molecule (supracritical methane) at a concentration of 10 mol
% in a variety of supracritical solvent systems (e.g., Ar, CO2, CF4, e
tc.). In this paper we look at a very different kind of solvent, supra
critical molecular hydrogen. It was chosen because of its well-known r
eorientational properties, i.e., quantum mechanical rotation in all ph
ases (except perhaps metallic H-2(s)). The results indicate that the I
/d vs d plots are more complicated than earlier systems studied and gi
ve good evidence of additional numbers of H-2 molecules clustered arou
nd the solute CH4. Hydrogen's absolute differential Raman rotational c
ross-section for Delta J = 1 --> 3 is very well known and combined wit
h the cross-section of the methane probe molecules' nu(1) symmetric st
retching vibration, it was possible to quantify and compare the contri
butions of various mechanisms known to be present in interaction-induc
ed Raman light scattering of a wide variety of solvents and to therefo
re judge their solvating capacities vis a vis CH4.