Excess infrared (IR) absorption spectroscopy, a new concept brought forward by applying the idea of excess thermodynamic functions to infrared spectroscopy, is shown to be a potential method to study hydrogen bonds. It can be applied to enhance spectral resolution of complexed IR bands, to evaluate nonideality of liquid mixtures, and to estimate selective molecular interactions. The sign of the excess infrared absorption coefficient is also of importance in providing information on molecular interactions. The results demonstrate that excess infrared absorption spectroscopy can unveil new information on hydrogen bonding in condensed phases.

Excess Infrared Absorption Spectroscopy and its Applications in the Studies of Hydrogen Bonds in Alcohol-Containing Binary Mixtures:

Condensation effect of cholesterol, stigmasterol, and sitosterol on dipalmitoylphosphatidylcholine in molecular monolayers

Excess thermodynamic properties are widely used quantitatively for fluids. It was found that at constant temperature and pressure a molar excess quantity of a mutually miscible binary mixture at the extreme points equals the excess partial molar quantities of the two components, i.e. F E 1 =F 2 E =F E m , forming a triple cross point. The relationship is hold for properties such as enthalpy, entropy, Gibbs free energy, and volume, and is applicable for excess functions with multi extreme points. Solutions at extreme points can be referred to as special mixtures. Particularly for a special mixture of Gibbs free energy, activity coefficients of the two components are identical.

YU Zhiwu

Papers

A principle to correlate extreme values of excess thermodynamic functions with partial molar quantities