Ground-state potential surface

While it is not essential to the method, frozen Gaussians have been used in all applications to date, that is, the width is kept fixed in the equation for the phase evolution. The widths of the Gaussian functions are then a further parameter to be chosen, although it appears that the method is relatively insensitive to the choice. One possibility is to use the width taken from the harmonic approximation to the ground-state potential surface [221]. 

The two coordinates defined for H4 apply also for the H3 system, and the conical intersection in both is the most symmetric structure possible by the combination of the three equivalent structures An equilateral triangle for H3 and a perfect tetrahedron for H4. These sbnctures lie on the ground-state potential surface, at the point connecting it with the excited state. This result is generalized in the Section. IV. 

Diagonalizing the corresponding 2x2 secular equation and some algebraic manipulation gives the four-electron ground-state potential surface... 

Exercise 2.1. Evaluate the ground-state potential surface for the CH3OCH3—> CH3 + CH30- reaction using the reaction field model, with a cavity radius a = R/2 + 1.5. 

Here (in contrast to the approach taken in Chapter 2) we do not assume that the energy of each valence bond structure is correlated with its solvation-free energy. Instead we use the actual ground-state potential surface to calculate the ground-state free energy. To see how this is actually done let s consider as a test case an SN2 type reaction which can be written as... 

Thakur, S. N., Goodman, L and Ozkabak, A. G. (1986), The Benzene Ground State Potential Surface. I. Fundamental Frequencies for the Planar Vibrations, J. Chem. Phys. 84, 6642. 

The adiabatic MOVE ground state potential surface is significantly lower in energy than the diabatic surfaces. The computed barrier for the proton transfer is 1.2 kcal/mol at the MOVE(3)/3-21G level, which may be compared with the... 

J. -L. Martin Prof. Zewail, how do you expect your work on pho-toinduced tautomerization of base pairs to apply to the real world of DNA, where such a reaction would happen on ground-state potential surface in a water environment ... 

The minimum of the excited state potential surface is displaced from that of the ground state potential surface by A = Q(excited state) — Q(ground state). The formula to convert the... 

The dynamics of the wavepacket on the upper potential surface determines both the absorption spectrum and the Raman spectrum. The emission spectrum is determined by the dynamics on the ground state potential surface with the same displacements as those which determine the absorption and Raman. In the short time limit, the intensities in the Raman spectrum are related to the displacements by eq. 7. In the short time limit, the absorption spectrum becomes... 

Vibrational echo experiments permit the use of optical coherence methods to study the dynamics of the mechanical degrees of freedom of condensed phase systems. Because vibrational transitions are relatively narrow, it is possible to perform vibrational echo experiments on well-defined transitions and from very low temperature to room temperature or higher. Further, vibrational echoes probe dynamics on the ground state potential surface. Therefore, the excitation of the mode causes a minimal perturbation of the solvent. 

A linear combination of the three diabatic states in equation (16) provides a good description of the ground state potential surface in all regions along the reaction coordinate, and the potential energy of the system is obtained by solving the secular equation (15) by diagonalizing the Hamiltonian matrix to yield... 

Hydrogen. The reaction of O ( D2) with H2 takes place on the ground state potential surface of water, HiOf Ai). On the basis of trajectory calculations, (Whitlock et al., 1982) it has been suggested that, as is true for the hydrocarbons, parallel mechanisms involving insertion/elimination and direct abstraction govern the course of this reaction. The observation using laser induced fluorescence spectroscopy (Luntz et al., 1979 Smith and Butler, 1980) of a highly excited, non-Boltzmann rotational distribution and a nearly statistical vibrational distribution for v" = 1 and v" = 0 is consistent with the insertion/elimination... 

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