TEMPERATURE DEPENDENCE OF THE SHAPE OF THE ROTATION-VIBRATION FUNDAMENTAL OF HCl IN SOLUTION

Author Institution: D\'epartment de Chimie, Universit\'e Laval, Qu\'ebec; Centre des Recherches sur les Atomes et Les Mol\'ecules, Universit\'e Laval, Qu\'ebecMoment analyses have been made of the rotation-vibration fundamental of HCl dissolved in a number of nonpolar solvents. The second moment of the band is found to vary linearly with temperature in agreement with Gordon’s theory. The fourth moment, which is a function of the torque acting on the solute molecule due to solute-solvent interaction, exhibits a more complex temperature dependence. The results will be interpreted using a simple model."

PROFILE OF THE ROTATION-VIBRATION FUNDAMENTAL OF HCl AND DCl IN SOLUTION

Author Institution:The correlation-function approach to the analysis of absorption-band shapes has been used in studies of HCl and DCl in $CC\ell_{4}$ solution over a range of temperatures. The isotope effect on the band moments will be discussed in terms of the rotation-translation coupling model

Pressure Locking of the Subgel Phase of Hydrated Dipalmitoyl Phosphatidylcholine Bilayers: A Raman Spectroscopic Study

Raman spectra of aqueous dispersions of 1,2-dipalmitoyl-phosphatidylcholine (DPPC) have been measured as a function of pressure (up to 46 kbar) for samples incubated at 2°C and for nonincubated DPPC samples subjected to equally high pressure. The nature of the transition from the GII gel phase of the hydrated lipid into the subgel phase on incubation is entirely different from that of the transition from the GII gel phase into the GIII gel phase of the nonincubated lipid. The GIII gel phase has a monoclinic interchain packing, while the subgel phase exhibits a triclinic interchain structure. It is shown that pressure cannot induce the transition from the GII gel phase to the subgel phase; however, it does stabilize the subgel phase above the subtransition temperature. The mechanism for the formation of the subgel phase and the complex phase behavior of the gel phase of DPPC are rationalized in terms of the dynamic properties of the acyl chains of the lipid molecule