Solvent effects polarizable continuum model

In addition to these external electric or magnetic field as a perturbation parameter, solvents can be another option. Solvents having different dielectric constants would mimic different field strengths. In the recent past, several solvent models have been used to understand the reactivity of chemical species [55,56]. The well-acclaimed review article on solvent effects can be exploited in this regard [57]. Different solvent models such as conductor-like screening model (COSMO), polarizable continuum model (PCM), effective fragment potential (EFP) model with mostly water as a solvent have been used in the above studies. 

As can be seen from the histogram in Figure l-l(b), the loose conformation is preferred over the tight one, a result only possible with inclusion of solvent effects. Ab-initio calculations of those conformers show that, without the inclusion of solvent effects, the tight conformer is preferred by 7.4 kcal/mol, while the inclusion of solvent effects (with polarizable continuum model, PCM) shifts the preference towards the loose conformer, which becomes more stable than the tight one by 0.1 kcal/mol. 

C. Amovilli, V. Barone, R. Cammi, E. Cancfes, M. Cossi, B. Menucci, C. S. Pomelli, and J. Tomasi, Recent advances in the description of solvent effects with the polarizable continuum model, Adv. Quantum Chem. 32 227 (1998). 

Since the Tomassi et a/.86,87 Polarizable Continuum Model, PCM, to describe dielectric solvent effects is implemented within the Gaussian9881 suite of programs, Peralta and Barone s modified version of the Gaussian98 suite of programs can be used to calculate solvent effects on the FC, SD and DSO terms (however for the FC term the perturbative FPT approach should be used if solvent effects are to be calculated). 

DFT was employed to study the mechanism of ammonolysis of phenyl formate in the gas phase, and the effect of various solvents on the title reaction was assessed by the polarizable continuum model (PCM). The calculated results show that the neutral concerted pathway is the most favourable one in the gas phase and in solution.24 The structure and stability of putative zwitterionic complexes in the ammonolysis of phenyl acetate were examined using DFT and ab initio methods by applying the explicit, up to 7H20, and implicit PCM solvation models. The stability of the zwitterionic tetrahedral intermediate required an explicit solvation by at least five water molecules with stabilization energy of approximately 35 kcalmol-1 25... 

Computational Modelling of the Solvent-Solute Effect on NMR Molecular Parameters by a Polarizable Continuum Model... 

B. Mennucci, J. Tomasi, R. Cammi, J. R. Cheeseman, M. J. Frisch, F. J. Devlin, S. Gabriel and P. J. Stephens, Polarizable Continuum Model (PCM) calculations of solvent effects on optical rotations of chiral molecules, J. Phys. Chem. A, 106 (2002) 6102-6113. 

Organometallic systems such as porphyrines have been investigated because of the possibility to fine tune their response by functionalization[105-107]. Systems of increased the dimensionality have been of particular interest [108-111], Concomitant to the large effort to establish useful structure-to-properties relationships, considerable effort has now been put to investigate the environmental effects on TPA[112-114], For example, the solvent effect has been studied for a small linear push-pull chromophore using a self-consistent reaction field (homogeneous solvation) method employing a spherical cavity and an internal force field (IFF) method[l 12] in another study the polarizable continuum model has been employed to calculate the relevant quantities to obtain the TPA cross-section in the limit of a two-state model[113] Woo et al. made a critical study of experimental comparison of TPA cross-sections in different solvents[114]. 

The most sophisticated methods developed to date to treat solvent effects in electronic interactions and EET are those reported by Mennucci and co-workers [47,66,67], Their procedure is based on the integral equation formalism version of the polarizable continuum model (IEFPCM) [48,68,69], The solvent is described as a polarizable continuum influenced by the reaction field exerted by the charge distribution of the donor and acceptor molecules. In the case of EET, it is the particular transitions densities that are important. The molecules are enclosed in a boundary surface that takes a realistic shape as determined by the molecular structure. 

At 638 nm in cyclohexane, the wavelength of maximum absorbance of the bis(naphtho[l,8-A ]thiopyranone) 628 is 98 nm to the red of thioindigo (Amax 540 nm). These values are in close agreement with those predicted by a TD-PBE0/6-311+G(2, />)//PBE0/6-311G6f,/>) approach that allowed for bulk solvent effects by means of a polarizable continuum model <2006JA2072>. 

Abstract The computational study of excited states of molecular systems in the condensed phase implies additional complications with respect to analogous studies on isolated molecules. Some of them can be faced by a computational modeling based on a continuum (i.e., implicit) description of the solvent. Among this class of methods, the polarizable continuum model (PCM) has widely been used in its basic formulation to study ground state properties of molecular solutes. The consideration of molecular properties of excited states has led to the elaboration of numerous additional features not present in the PCM basic version. Nonequilibrium effects, state-specific versus linear response quantum mechanical description, analytical gradients, and electronic coupling between solvated chromophores are reviewed in the present contribution. The presentation of some selected computational results shows the potentialities of the approach. 

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