Nonadiabatic processes may involve both classical-like and quantum-like coordinates. A semiclassical analysis is used to treat the contribution of the former to the Franck-Condon factor in the reaction rate expression, thereby avoiding the usual harmonic oscillator approximation. Microcanonical and canonical rate constants are calculated, yielding an expression which includes contributions from...

We investigate phase-sensitive interference effects in a periodically sin(2πfrf t)driven, artificial two-state system connected to a microwave resonator at fLC ≃ 800 MHz. We observe two kinds of multiphoton transitions in the two-state system, accompanied by: 1) Several quanta from the drive at frf and 2) one quantum at frf and several at fLC . The former are described using phase-sensitive Lan...

For the first time, two hydrogen-deficient hydrocarbon radicals are generated in situ via laser ablation of graphite and seeding the ablated species in acetylene gas, which acts as a carrier and reactant simultaneously. By recording photoionization efficiency curves (PIE) and simulating the experimental spectrum with computed Franck-Condon (FC) factors, we can reproduce the general pattern of t...

Abstract Cyclobutane thymine dimerization is the most prominent DNA photoinduced damage. While the ultrafast mechanism that proceeds in the singlet manifold is nowadays well established, the triplet-state pathway is not completely understood. Here we report the underlying mechanism of the photosensitized dimerization process in the triplet state. Quantum chemical calculations, combined with wav...

High resolution photoelectron spectroscopy of Au4 (-) is reported using a new photoelectron imaging apparatus. A broad vibrational progression is resolved for the detachment transition from the ground electronic state of the Y-shaped Au4 (-) to that of the Y-shaped Au4 neutral (C2v, (1)A1) in the ν2 vibrational mode with a harmonic frequency of 171(7) cm(-1) and an anharmonicity of ∼0.5 cm(-1)....

The photodetachment spectrum of HHfO- was simulated using restricted-spin coupled-cluster single-double plus perturbative triple {RCCSD(T)} calculations performed on the ground electronic states of HHfO and HHfO-, employing basis sets of up to quintuple-zeta quality. The computed RCCSD(T) electron affinity of 1.67 ± 0.02 eV at the complete basis set limit, including Hf 5s25p6 core correlation a...

Electron emission from the negative electron affinity (NEA) surface of hydrogen terminated, boron doped diamond in the [100] orientation is investigated using angle resolved photoemission spectroscopy (ARPES). ARPES measurements using 16 eV synchrotron and 6 eV laser light are compared and found to show a catastrophic failure of the sudden approximation. While the high energy photoemission is f...

Our new simple method for calculating accurate Franck-Condon factors including nondiagonal (i.e., mode-mode) anharmonic coupling is used to simulate the C2H4+X2B3u<--C2H4X1A(g) band in the photoelectron spectrum. An improved vibrational basis set truncation algorithm, which permits very efficient computations, is employed. Because the torsional mode is highly anharmonic it is separated from the...