Calculation of electron affinities of polycyclic aromatic hydrocarbons and solvation energies of their radical anion.

Electron affinities (EAs) and free energies for electron attachment (DeltaGo(a,298K)) have been directly calculated for 45 polynuclear aromatic hydrocarbons (PAHs) and related molecules by a variety of theoretical methods, with standard regression errors of about 0.07 eV (mean unsigned error = 0.05 eV) at the B3LYP/6-31 + G(d,p) level and larger errors with HF or MP2 methods or using Koopmans' Theorem.

The phototoxicity of polycyclic aromatic hydrocarbons: a theoretical study of excited states and correlation to experiment.

Investigators using models to determine the phototoxic effects of sunlight on polycyclic aromatic hydrocarbons (PAHs) have invoked the excited states of the molecule as important in elucidating the mechanism of these reactions. Energies of actual excited states were calculated for ten PAHs by several ab initio methods. The main method used for these calculations was the Configuration Interaction approach, modeling excited states as combinations of single substitutions out of the Hartree-Fock ground state.

A kinetic study of the methanolysis of the sulfonylureas bensulfuron methyl and sulfometuron methyl using capillary electrophoresis.

The instability of sulfonylureas in solution in methanol has led us to a kinetic study of methanolysis of two sulfonylureas using capillary electrophoresis. In a preliminary experiment, solutions of the seven compounds, bensulfuron methyl, sulfometuron methyl, nicosulfuron, chlorimuron ethyl, thifensulfuron methyl, metsulfuron methyl, and chlorsulfuron were prepared in methanol and in acetonitrile. After six weeks at room temperature the compounds dissolved in acetonitrile were quite stable as shown by electropherograms obtained with free zone capillary electrophoresis (CE).

Measurement of high-molecular-weight polycyclic aromatic hydrocarbons in soils by particle beam high-performance liquid chromatography-mass spectrometry.

Polycyclic aromatic hydrocarbons (PAHs) comprise a class of potentially hazardous com- pounds of concern to the U.S. EPA.

Evidence for thermal decomposition contributions to the mass spectra of chlorinated phenoxyacid herbicides obtained by particle beam liquid chromatography mass spectrometry.

The spectral quality of a group of chlorinated phenoxyacid herbicides has been shown to degrade under certain conditions upon introduction into the mass spectrometer by a particle beam interface. Experiments were performed to investigate these changes in spectra. Normalized ion chromatograms were generated for the herbicides, and the results showed a broadening of the profiles of some ions, indicating a longer residence time in the ion source.