The H and D atom elimination mechanisms in the photodissociation of jet cooled pyrrole and pyrrole-d1 have been studied by photofragment velocity map imaging. The molecules were excited to the 1 1A2 (pi sigma*) state at lambda = 243 nm and to the 1 1B2 (pi pi*) state at lambda = 217 nm. H/D atoms were detected by (2 + 1) resonance enhanced multiphoton ionization (REMPI) at lambda = 243 nm. The ...

Semiclassical electron-radiation-ion dynamics simulations are reported for the photodissociation of cyclobutane into two molecules of ethylene. The results clearly show the formation of the tetramethylene intermediate diradical, with dissociation completed in approximately 400 fs. In addition, the potential energy surfaces of the electronic ground state and lowest excited-state were calculated ...

We perform extensive density-functional theory total-energy calculations and ab-initio molecular dynamics simulations to evaluate the stability and reactivity of surface oxides and hydroxides of InP(001) for photoelectrochemical water cleavage. In order to achieve maximal accuracy, our simulations include the full interface between the semiconductor surface and liquid water. Certain oxide conta...

We used temperature programmed reaction spectroscopy (TPRS) and molecular beam reflectivity measurements to investigate the initial dissociation of n-butane isotopologues on PdO(101) and determine kinetic parameters governing the selectivity of initial C-H(D) bond cleavage. We observe differences in the reactivity of the n-butane isotopologues on PdO(101) due to kinetic isotope effects, and fin...

We present an ab initio molecular dynamics algorithm at the generalized valence bond level. It does not need a precalculated potential energy surface or model Hamiltonian; instead the nuclei move according to first principles forces derived from the electronic wave function which in turn follows the movement of the nuclei. This technique includes the dominant static electron correlations, it ca...

Direct characterization of peptides with multiple disulfide bonds by mass spectrometry is highly desirable. In this study, electron transfer dissociation (ETD) of peptide disulfide regio-isomers was studied using model peptides containing two intrachain disulfide bonds. ETD provided rich sequence information (c/z ions) even for the backbone region under the coverage of two disulfide bonds. This...

An analysis of molecular properties is presented for several first-row diatomic molecules as determined at the CCSD~T! level of theory. In particular, a comparison of spectroscopic constants predicted by the ROHF-CCSD~T! methods of Scuseria vs Gauss et al. is given. Accurate determination of the values of equilibrium bond lengths, dissociation energies, harmonic vibrational frequencies, anharmo...