Time-dependent quantum mechanical calculations on the formation of molecular hydrogen on a graphite surface via an Eley-Rideal mechanism by Meijer, A, Farebrother, A, Clary, D, Fisher, A

“…In our calculations we used a time-dependent wave packet method treating three degrees of freedom quantum mechanically. A newly developed potential energy surface based on plane-wave density functional calculations was employed. …”

Calculation of the photodetachment spectrum for H3O- by Clary, D, Gregory, J, Jordan, M, Kauppi, E

“…This method treats explicitly three active degrees of freedom (two stretching vibrations and one bending mode) in both H3O- and the neutral reactive product. …”

Quantum dynamics and kinetics of the abstraction reactions by H atoms of primary and secondary hydrogens in C3H8 by Kerkeni, B, Clary, D

“…The potential energy surfaces were computed by treating explicitly the forming and breaking bonds during the reaction, and optimizing the geometries of all the remaining degrees of freedom. In this way, the dynamics of the reaction occurs on an effective reduced dimensionality hyper-surface accounting for the zero-point energy of the optimized degrees of freedom. …”

Quantum reactive scattering of H + hydrocarbon reactions. by Kerkeni, B, Clary, D

“…The ab initio potential energy surfaces for these reactions can be built from a minimal number of grid points (average of 50 points) and expressed in terms of analytical functionals. All the degrees of freedom except the breaking and forming bonds are optimised using the MP2 method with a cc-pVTZ basis set. …”

Predicting conformations of biomolecules: Application to a noradrenaline analogue by Miller, T, Clary, D

“…The TPIMC method is a general approach to the thermodynamic simulation of large molecules that treats anharmonicity and quantum effects within the torsional degrees of freedom.…”

A method to calculate vibrational frequency shifts in heteroclusters: Application to N-2(+)-He-n by Brown, D, Gregory, J, Clary, D

“…We use diffusion Monte Carlo to simulate the 3n degrees of freedom of the N2+-Hen interactions while the N-N vibrational motion is solved by an adiabatic method. …”

Torsional path integral Monte Carlo method for the quantum simulation of large molecules by Miller, T, Clary, D

“…The torsional path integral Monte Carlo (TPIMC) technique applies an uncoupled winding number formalism to the torsional degrees of freedom in molecular systems. The internal energy of the molecules such as ethane, n-butane and n-octane were calculated at standard temperature using the TPIMC technique and were compared to the expectation values obtained using the harmonic oscillator approximation and a variational technique. …”

Rate constants for the CH4+H -> CH3+H-2 reaction calculated with a generalized reduced-dimensionality method by Palma, J, Echave, J, Clary, D

“…Calculations were performed using a reduced-dimensionality model with four degrees of freedom and two different methods to convert reduced-dimensionality reaction probabilities into rate constants. …”

Semiclassical transition state theory for chemical reactions by Greene, S

“…Further gains in efficiency can be achieved by calculating anharmonic constants for only a subset of degrees of freedom. SCTST can be improved by imposing more realistic behaviour of the reactant and product asymptotes of the potential barrier used in calculations.…”

Reactive resonances in the F + CHD3 reaction--a quantum dynamics study. by von Horsten, H, Clary, D

“…In our reduced dimensionality study we treat the two most important degrees of freedom, which describe the bond making and bond breaking explicitly, while treating the remaining spectator modes adiabatically. …”

Torsional path integral Monte Carlo method for calculating the absolute quantum free energy of large molecules by Miller, T, Clary, D

“…The quantum contributions to torsional degrees of freedom are treated in a fashion that converges systematically to the exact result. …”

A NEW METHOD FOR CALCULATING THE ROVIBRATIONAL STATES OF POLYATOMICS WITH APPLICATION TO WATER DIMER by Althorpe, S, Clary, D

“…This new "DVR-ISE" method can be successfully applied to molecules whose dynamics involve strong coupling between all degrees of freedom. To demonstrate this it is applied to (H 2O)2 in calculations of the lowest few energy levels for intermolecular angular motion. …”

Influence of surface defects on the adsorption of HCl on ice by Clary, D, Wang, L

“…A mixed quantum-classical method is used that involves treating the vibrational and translational motion of HCl using time-dependent quantum mechanics while classical mechanics is used to describe all other degrees of freedom including those of 360 water molecules representing ice. …”

The effect of the symmetric and asymmetric stretching vibrations on the CH3D+O(P-3)-> CH3+OD reaction by Palma, J, Echave, J, Clary, D

“…We report calculations on the CH3D + O(3P) → CH3 + OD reaction using a reduced dimensionality model with four degrees of freedom. The model has already been used to evaluate the effect of the symmetric and asymmetric stretching vibrations of methane on the CH4 + O(3P) and CH4 + H reactions. …”

Quantum free energies of the conformers of glycine on an ab initio potential energy surface by Miller, T, Clary, D

“…The 3-dimensional torsional potential energy surface of glycine was obtained at the MP2/6-311++G** level of theory and is optimized with respect to the non-torsional degrees of freedom. Calculated conformer populations compare well with those reported in recent matrix-isolation infrared spectroscopy experiments. …”

H-2 dissociation on metal surfaces: Six-dimensional approximate quantum calculations by Munn, N, Clary, D

“…Using hyperspherical coordinates, we show how the six-dimensional (6D) H2/metal surface dissociation problem may be reduced to two dimensions by treating explicitly the bonds breaking and forming, while adding zero-point energy corrections to , the effective potential for all other degrees of freedom. We present calculations of reaction probabilities for dissociation of H2 on Ni(100) in three dimensions and on Cu(111) in four dimensions using this approach, and show their substantial agreement with those obtained using far more expensive exact methods. …”

Quantum scattering calculations on the S(N)2 reaction Cl-+CH3Br -> ClCH3+Br- by Schmatz, S, Clary, D

“…The C-Br and C-Cl stretching degrees of freedom (quantum numbers v and v′) and the azimuthal angle (rotation of the CH3 group; quantum numbers k and k′) are treated explicitly. …”

The effect of the torsional and stretching vibrations of C2H6 on the H + C2H6 --> H2 + C2H5 reaction. by Kerkeni, B, Clary, D

“…The model allows the torsional and the stretching degrees of freedom to be treated explicitly. Zero-point energies of the remaining modes are taken into account in electronic structure calculations. …”

QUANTUM AND QUASI-CLASSICAL CALCULATIONS ON THE OH+CO-]CO2+H REACTION by Clary, D, Schatz, G

“…The comparisons of quantum and quasiclassical calculations for models that treat explicitly different numbers of degrees of freedom provide detailed insight into the dynamics of the OH+CO reaction. © 1993 American Institute of Physics.…”

Quantum dynamics of the Walden inversion reaction Cl-+CH3Cl->ClCH3+Cl- by Clary, D, Palma, J

“…The rotating bond approximation (RBA) has been adapted so that three degrees of freedom including the C-Cl stretching vibration and the CH3 umbrella mode are treated explicitly. …”