Density dependence of attractive forces for hydrogen stretching vibrations of molecules in compressed liquids

摘要: An empirical analysis of pressure‐induced shifts for quasidiatomic C–H or O–H stretching vibrations in solution shows that the portion attributable to attractive forces exhibits an approximately quadratic dependence on solvent density, with exponents range sA=2.1±0.3 ten systems. This is much stronger than linear density (sA=1) postulated by Schweizer and Chandler. Theoretical estimates part frequency are derived averaging R−n potentials (n≥6) using hard‐sphere radial distribution function. yields a simple, explicit formula exponential density. We find sA∼2.0±0.1 experimental regime, whereas sA→1 zero‐density limit. The sA values at high insensitive potential exponent n comparable repulsive sR∼3.5 obtained from model. as well ...