G. N. Lewis' atom and quantum Monte Carlo studies of liquids

Liquids that involve changes in electronic structure are difficult to simulate using pairwise additive forces. In this paper we use a semiempirical model of the internal structure of atoms in order to simulate simultaneously electronic and nuclear dynamics of fluids. The proposed excitonic phase of mercury is critically examined with these models.     

Fourier transform infrared spectral study of N,N′-dimethylformamide-water-rhodamine 6G mixture

Infrared absorption spectra of N,N′-dimethyl formamide in the absence and presence of water, rhodamine 6G and water–rhodamine 6G mixture are reported. Assignment of observed bands has been made on the basis of density functional theory calculations and available assignments in the literature. Certain bands show changes in their positions and intensities when water is added to N,N′-dimethylformamide. This is due to hydrogen bonding interaction between these molecules. Similar changes are also observed for dimethylformamide and Rh6G mixture to a lesser extent. The presence of Rh6G in a dimethylformamide–water mixture reverses these spectral changes due to preferential solvation of Cl^? by water molecules. Solvation reduces or nullifies the hydrogen bonding between dimethylformamide and water in the mixture.     

Comments on the paper «Fluorescence decay of indole in water» by N. Periasamy and G. C. Joshi

Summary Examples of multiexponential decay of indole are reported. Problems connected with the minimization procedure are also outlined.     

Introduction to Quantum Statistical Mechanics, 2nd edn., by N.N. Bogolubov and N.N. Bogolubov Jr

The mobility and self-diffusion of polymer molecules in concentrated systems or in the molten bulk state is largely controlled by entanglements between the molecules. These entanglements are a result of the chain-like nature of the molecules and of their extended, coil-like configuration. The conformation and mobility of polymer molecules in dilute solution—which are relatively well understood—are discussed; this leads to a consideration of self-diffusion in the more concentrated states and in the bulk polymer melt, and several special properties of polymers which are controlled and modified by the molecular self-diffusion are examined.

Our current theoretical understanding of polymeric self-diffusion in highly entangled systems is outlined, and the ways in which such diffusion may be studied experimentally are briefly described. The final part of the review describes a recent experimental study of self-diffusion in a polymer melt; the results of this study may provide new insight into the motion of entangled, chain-like molecules.