Dynamic polarization model

Iwata K, Ozawa R, Hamaguchi H (2002) Analysis of the solvent- and temperature-dependent Raman spectral changes of S1 trans-stilbene and the mechanism of the trans to cis isomerization dynamic polarization model of vibrational dephasing and the C=C double-bond rotation. J Phys Chem A 106 3614—3620... 

Closing naphthyl ring. The induced dipole moment is then chirally disposed in relation to the inducing NH2 dipole moment. This mechanism, referred to as the dynamic polarization model (45), is shown to explain most of the observed VCD intensity in the synunetric NH2 stretching mode, >>nh2- The anisotropy ratio for this VCD band is ca. 10. Since an NH. . . x type hydrogen bond is possible in this molecule, a description based on vibrationally induced charge flow (currents) may also be riuitfiil, similar to that proposed for a-phenyleth-ylamine. Sect. FV-B-2. 

Picosecond Raman measurements have led to the proposal of a dynamic polarization model." In this model, 5i tS undergoes reversible changes in vibrational frequencies that are induced by solvent fluctuations. The mixing of a perturbing state with interconverts carbon-carbon double bonds with single bonds that leads S tS near the vertical geometry to proceed along the pathway for isomerization. 

C. J. Barnett, A. F. Drake, R. Kuroda, and S. F. Mason, Mol. Phys., 41, 455 (1980). A Dynamic Polarization Model for Vibrational Optical Activity and the Infrared Circular Dichroism of a Dihydro[5]helicene. 

Van der Zwan G and Hynes J T 1982 Dynamical polar solvent effects on solution reactions A simple continuum model J. Chem. Phys. 76 2993-3001... 

Mason SF (1980) The Ligand Polarization Model for the Spectra of Metal Complexes. The Dynamic Coupling Transition Probabilities. 39 43-81 Massey V, see Hemmerich P (1982) 48 93-124... 

Stillinger FH (1979) Dynamics and ensemble averages for the polarization models of molecular interactions. J Chem Phys 71(4) 1647... 

G. R. Lawler, Chemically Induced Dynamic Polarization (CIDNP). II. The Radical-Pair Model," Accfs. Chem. Res. 5, 25 (1972). 

The semi-empirical bond polarization model is a powerful tool for the calculation of, 3C chemical shift tensors. For most molecules the errors of this model are in the same order of magnitude as the errors of ab initio methods, under the condition that the surrounding of the carbon is not too much deformed by small bond angles. A great advantage of the model is that bond polarization calculations are very fast. The chemical shift tensors of small molecules can be estimated in fractions of a second. There is also virtually no limit for the size of the molecule. Systems with a few thousand atoms can be calculated with a standard PC within a few minutes. Possible applications are repetitive calculations during molecular dynamics simulations for the interpretation of dynamic effects on 13C chemical shift distribution. 

F. Ingrosso, B. Mennucci and J. Tomasi, Quantum mechanical calculations coupled with a dynamical continuum model for the description of dielectric relaxation time dependent Stokes shift of coumarin Cl53 in polar solvents, J. Mol. Liq., 108 (2003) 21 -6. 

However, these molecular modeling techniques, like molecular dynamics calculations and dynamic polar surface calculations, require expensive computer time. Hydrogen bond formation and molecular volume turned out to be the most important... 

In the dynamic triplet model a similar dependence of polarization magnitude on plane-polarized light is predicted, provided that the ISC rate exceeds the molecular reorientation rate. 

Mason, S. F. The Ligand Polarization Model for Ae Spectra of Metal Complexes The Dynamic Coupling Transition Probabihties. Vol. 39, pp. 43-81. 

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