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Articles 1 - 7 of 7
Full-Text Articles in Biological and Chemical Physics
The Schrödinger Equation With Friction From The Quantum Trajectory Perspective, Sophya V. Garashchuk, Vaibhav Dixit, Bing Gu, James Mazzuca
The Schrödinger Equation With Friction From The Quantum Trajectory Perspective, Sophya V. Garashchuk, Vaibhav Dixit, Bing Gu, James Mazzuca
Faculty Publications
Similarity of equations of motion for the classical and quantum trajectories is used to introduce afriction term dependent on the wavefunction phase into the time-dependent Schrödingerequation. The term describes irreversible energy loss by the quantum system. The force offriction is proportional to the velocity of a quantum trajectory. The resulting Schrödinger equationis nonlinear, conserves wavefunction normalization, and evolves an arbitrary wavefunction into the ground state of the system (of appropriate symmetry if applicable). Decrease in energy is proportional to the average kinetic energy of the quantum trajectory ensemble. Dynamics in the high friction regime is suitable for simple models of …
Modeling The Noble Metal/Tio2 (110) Interface With Hybrid Dft Functionals: A Periodic Electrostatic Embedded Cluster Model Study, Salai Cheettu Ammal, Andreas Heyden
Modeling The Noble Metal/Tio2 (110) Interface With Hybrid Dft Functionals: A Periodic Electrostatic Embedded Cluster Model Study, Salai Cheettu Ammal, Andreas Heyden
Faculty Publications
The interaction of Aun and Ptn (n=2,3) clusters with the stoichiometric and partially reduced rutile TiO2 (110) surfaces has been investigated using periodic slab and periodic electrostatic embedded cluster models. Compared to Au clusters, Pt clusters interact strongly with both stoichiometric and reduced TiO2 (110) surfaces and are able to enhance the reducibility of the TiO2 (110) surface, i.e., reduce the oxygen vacancy formation energy. The focus of this study is the effect of Hartree–Fock exchange on the description of the strength of chemical bonds at the interface of Au/Pt clusters and the TiO2 (110) surface. Hartree–Fock exchange helps describing …
Semiclassical Application Of The Mo/Ller Operators In Reactive Scattering, Sophya V. Garashchuk, J. C. Light
Semiclassical Application Of The Mo/Ller Operators In Reactive Scattering, Sophya V. Garashchuk, J. C. Light
Faculty Publications
Mo/ller operators in the formulation of reaction probabilities in terms of wave packet correlation functions allow us to define the wave packets in the interaction region rather than in the asymptotic region of the potential surface. We combine Mo/ller operators with the semiclassical propagator of Herman and Kluk. This does not involve further approximations and can be used with any initial value representation (IVR) semiclassical propagator. Time propagation in asymptotic regions of the potential due to Mo/ller operators reduces the oscillations of the propagator integrand and improves convergence of the results with respect to the number of trajectories. The effectiveness …
Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya V. Garashchuk, D. J. Tannor
Correlation Function Formulation For The State Selected Total Reaction Probability, Sophya V. Garashchuk, D. J. Tannor
Faculty Publications
A correlation function formulation for the state-selected total reaction probability, Nα(E), is suggested. A wave packet, correlating with a specific set of internal reactant quantum numbers, α, is propagated forward in time until bifurcation is complete at which time the nonreactive portion of the amplitude is discarded. The autocorrelation function of the remaining amplitude is then computed and Fourier transformed to obtain a reactivity spectrum. Dividing by the corresponding spectrum of the original, unfiltered, wave packet normalizes the reactivity spectrum, yielding the total reaction probability from the internal state, α. The procedure requires negligible storage and just one time-energy Fourier …
Π-Systems As Lithium/Hydrogen Bond Acceptors: Some Theoretical Observations, Salai Cheettu Ammal, P. Venuvanalingam
Π-Systems As Lithium/Hydrogen Bond Acceptors: Some Theoretical Observations, Salai Cheettu Ammal, P. Venuvanalingam
Faculty Publications
Ab initio calculations at the Hartree–Fock and correlated levels and density functional theory calculations have been performed with 6-31++G(d,p) and 6-311++G(d,p)basis sets on LiF and HF complexes of benzene, ethylene, and acetylene. Complex binding energies have been corrected for basis set superposition error, and zero point energy corrections have been done on Hartree–Fock binding energies. Computed results indicate that the complexes exist in different conformations and among them those with π-lithium and π-hydrogen bonds are the most stable. π-lithium bonds are stronger than π-hydrogen bonds. The computed binding energies and geometry of HF complexes correlate well with the available experimental …
Semiclassical Approach To The Hydrogen-Exchange Reaction Reactive And Transition-State Dynamics, Sophya V. Garashchuk, F. Grossmann, D. Tannor
Semiclassical Approach To The Hydrogen-Exchange Reaction Reactive And Transition-State Dynamics, Sophya V. Garashchuk, F. Grossmann, D. Tannor
Faculty Publications
Scattering matrix elements and symmetric transition-state resonances for the collinear H 2 + H → H + H 2 reaction are obtained using a time-dependent approach. The correlation function between reactant channel wavepackets and product channel wavepackets is used to determine the S-matrix elements. In a similar fashion, autocorrelation functions are used to extract the positions and widths of transition-state resonances. The time propagation of the wavepackets is performed by the improved semiclassical frozen Gaussian method of Herman and Kluk, which is an initial value, uniformly converged method. The agreement between the quantum and semiclassical results is far better …
Lithium Bonding Interaction In H2Cy⋯Lif (Y=O,S) Complexes: A Theoretical Probe, Salai Cheettu Ammal, P. Venuvanalingam, S. Pal
Lithium Bonding Interaction In H2Cy⋯Lif (Y=O,S) Complexes: A Theoretical Probe, Salai Cheettu Ammal, P. Venuvanalingam, S. Pal
Faculty Publications
Ab initio calculations at 6-31++G(d,p) level have been done on H2CY⋯LiF (Y=O,S) complexes choosing ten possible orientations in each complex. The effect of correlation on complex binding energies has been studied via single point MP2 (full) calculations done on 6-31++G(d,p) geometry. Binding energies have been corrected for basis set superposition error. Frequency calculations confirm that H2CO⋯LiF and H2CS⋯LiF complexes have three and two stable forms, respectively. The most stable form in each complex has been found to have a strong lithium bonding interaction and a secondary hydrogen bondinginteraction. NBO analysis has revealed that in this form oxygen donates nσ lone …