Geometry relaxation

Starting from the assumption that the geometry relaxation after excitation is of primary importance with respect to the luminescence response, we decided to employ a solid polymer matrix to suppress conformational changes of the oligomers. For the measurements, dilute blends with polysulfone as the transparent host matrix were prepared. In Figure 16-13, the PL decay curves for the two cyano compounds in both chloroform and polysulfone are presented, as are the PL spectra of Ooct-OPV5-CN in chloroform and polysulfone [69J. 

Magyar, R.J., Mujica, V., Marquez, M. and Gonzalez, C. (2007) Density-functional study of magnetism in bare Au nanodusters Evidence of permanent size-dependent spin polarization without geometry relaxation. Physical Review B -Condensed Matter, 75,144421-1—144421-7. 

Drew, A. 2006. Influence of geometry relaxation on the energies of the Sj and S2 states of violaxanthin, zeax-anthin and lutein. J. Phys. Chem. A 110 4592 -599. 

F. Vanhouteghem, W. Pyckhout, C. Van Alsenoy, L. Van den Enden, and H. J. Geise, The molecular structure of gaseous allyl alcohol determined from electron diffraction, microwave, infrared and geometry relaxed ab initio data. J. Mol. Struct. 140, 33 48 (1986). 

Ion Ref. Basis set1) Uncontracted Contracted H2O geometry2) unperturbed Interaction energy2) with rigid H2O -AE Complex geometry2) with H2O geometry relaxed Optimized2) -AE... 

Dreuw, A. Influence of Geometry Relaxation on the Energies of the Sj and Sj States of Violaxanthin, Zeaxanthin, and Lutein./. Phys. Chem. A 2006,110, 4592-4599. 

While the CP procedure is exact only in the case of Full Cl wavefimctions, the a priori SCFMI method is always correct and geometry relaxation effects are naturally taken into account. 

We evaluated geometry relaxation in the lowest five excited electronic states and the Stokes shift values employing the Cs-symmetric Al(OH)4 model cluster. Geometric parameters for various electronic states were optimized at the CASSCF level and the resulting bond lengths, bond angles, and torsional angles are presented in Table 4.9. The optimized structures of the two lowest 12A" and 12A states with the hole localized on the O center are... 

The PCM/DFT model failed to predict the intrinsic rotation (i.e. the specific rotation extrapolated to infinite dilution) of (R)-3-methylcyclopentanone dissolved in carbon tetrachloride, methanol and acetonitrile [68], This molecule has been investigated because it exists in both an equatorial and an axial form, allowing researchers to investigate the interplay of solvent and conformational effects. The conformer populations used in the Boltzmann averaging were derived from IR absorption and VCD spectra. The deviation of the calculated optical rotation from experiment was found actually to be larger when IEF-PCM was used to account for direct solvent effects (and geometry relaxation) on the optical rotation than when the gas-phase values were used. 

More challenging and complex is the representation of the inter-relationship between geometry relaxation and electrostatic response. We will develop a general formalism to analyse this point, using the Miertus-Scrocco-Tomasi model (MST or PCM [1,2,5-7]) continuum formalism as a general framework for solvation description. However, all the physical principles presented here can be transfer to any other solvation model. 

Table 4.1 Effect of solvent-induced geometry relaxation on dipole moment. As noted in the text, all dipoles were computed using gas phase-like wavefunctions, i.e. neglecting solvent polarization of solute charge distribution...

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