Molecular dynamics and head-tail disorder in the Raman spectrum of crystalline N2O

Nonadiabatic dynamics of charge transfer in diatomic anion clusters

We have studied the photodissociation and recombination dynamics of the diatomic anions X(2)(-) and XY(-) designed to mimic I(2)(-) and ICl(-), respectively, by using a one-electron model in size-selected N(2)O clusters. The one-electron model is composed of two nuclei and an extra electron moving in a two-dimensional plane including the two nuclei. The main purpose of this study is to explain the salient features of various dynamical processes of molecular ions in clusters using a simple theoretical model. For heteronuclear diatomic anions, a mass disparity and asymmetric electron affinity between the X and Y atoms lead to different phenomena from the homonuclear case. The XY(-) anion shows efficient recombination for a smaller cluster size due to the effect of collision-mediated energy transfer and an inherent potential wall on excited state at asymptotic region, while the recombination for the X(2)(-) anion is due to rearrangement of solvent configuration and faster nonadiabatic transitions. The results of the present study illustrate the microscopic details of the electronically nonadiabatic processes which control the photodissociation dynamics of molecular ions in clusters.

Interactions of Nitrous Oxide with Fluorinated Liquids

The interactions of nitrous oxide with fluorinated liquids are investigated by reporting original experimental results on gas solubility and interpreting them using molecular simulation. Nitrous oxide is highly soluble in the three fluorinated liquids studied-perfluorooctane, 1-bromoperfluorooctane (perfluorooctylbromide), and perfluorohexylethane-with mole fraction solubilities on the order of 0.03 under ambient conditions. An intermolecular potential model was developed for nitrous oxide, with a functional form of the Lennard-Jones plus point charges type, adjusted to the experimental multipole moments and to vapor-liquid equilibrium properties. The solubility of nitrous oxide in perfluorocarbon liquids was calculated by molecular simulation methods, and a dissimilar interaction parameter of 0.92 in the Lennard-Jones well-depths between solute and solvent had to be introduced to reach agreement with the experimental results, similar to what is found for hydrocarbon-fluorocarbon interactions. The structure of the solutions was studied by analysis of solute-solvent radial distribution functions, showing that, although electrostatic interactions are not predominant, a small orientational effect is still present between the dipole of nitrous oxide and those of the substituted fluorinated liquids.

Monte Carlo simulations of I2- (CO2)16 and I2- (N2O)16 clusters. Minimum energy structures and solvation energy

Structures of the I2- (CO2)16 and I2- (N2O)16 clusters have been studied along the dissociation path of the halide ion. Minimum energy structures and solvation energies have been estimated. The influence of the electrostatic interaction on the I2- charge distribution and the structure of the solvation shell has been discussed. It has been shown that the small dipole moment of the N2O molecule does not have much influence on the cluster properties, and the large quadrupole moments of both solvent clusters give the major contribution into electrostatic interactions. The structure of the clusters is more sensitive to different potential models than to the dipole moment of the N2O molecule.