Trajectory simulations of molecular collisions

The first energy derivative is called the gradient g and is the negative of the force F (with components along the a center denoted Fa) experienced by the atomic centers F = -g. These forces, as discussed in Chapter 16, can be used to carry out classical trajectory simulations of molecular collisions or other motions of large organic and biological molecules for which a quantum treatment of the nuclear motion is prohibitive. 

Quantum-Classical Methods Trajectory Simulations of Molecular Collisions Classical Treatment. 

The general understanding of molecular dynamics rests mainly upon classical mechanics this holds true for full bimolecular collisions (see Trajectory Simulations of Molecular Collisions Classical Treatment) as well as half-collisions, i.e., the dissociation of a parent molecule into different products. The classical picture of photodissociation closely resembles the time-dependent picture the electronic transition from the ground to the excited electronic state is assumed to take place instantaneously so that the internal coordinates (Qi) and corresponding momenta (/, ) of the parent molecule remain unchanged during the excitation step (vertical transition). After the molecule is promoted to the PES of the upper state it starts to move subject to the classical equations of motion (Hamilton s equations)... 

Classical Dynamics of Nonequilibrium Processes in Fluids Integrating the Classical Equations of Motion Control of Microworld Chemical and Physical Processes Mixed Quantum-Classical Methods Multiphoton Excitation Non-adiabatic Derivative Couplings Photochemistry Rates of Chemical Reactions Reactive Scattering of Polyatomic Molecules Spectroscopy Computational Methods State to State Reactive Scattering Statistical Adiabatic Channel Models Time-dependent Multiconfigurational Hartree Method Trajectory Simulations of Molecular Collisions Classical Treatment Transition State Theory Unimolecular Reaction Dynamics Valence Bond Curve Crossing Models Vibrational Energy Level Calculations Vibronic Dynamics in Polyatomic Molecules Wave Packets. 

Reaction Path Hamiltonian and its Use for Investigating Reaction Mechanisms Scaled Particle Theory Trajectory Simulations of Molecular Collisions Classical Treatment Transition State Theory. 

TRAJECTORY SIMULATIONS OF MOLECULAR COLLISIONS CLASSICAL TREATMENT 3057... 

This account highlights some of the recent developments in methods and current applications of classical trajectory simulations of molecular collisions. It has been more than 60 years since the first classical trajectory calculation was attempted on a mechanical calculator and almost 40 years since the first ensembles of trajectories were calculated on a digital computer and, even though the real world is quantum mechanical, classical trajectory simulations continue to play a crucial role in studies of chemical dynamics. The classical approximation, fortunately, is valid for many processes and conditions of interest to chemists, and the Monte Carlo quasiclassical trajectory approach is relatively simple and straightforward to apply. The work reviewed here clearly illustrates that it continues to be used productively, creatively, and widely, to study the details of chemical processes. 

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