A simple heuristic approach to estimate the thermochemistry of condensed-phase molecules based on the polarizable continuum model

2019 ◽  
Vol 21 (35) ◽  
pp. 18920-18929 ◽  
Author(s):  
Yu-ichiro Izato ◽  
Akira Matsugi ◽  
Mitsuo Koshi ◽  
Atsumi Miyake
Keyword(s):  
Liquid Phase ◽  
Simple Model ◽  
Condensed Phase ◽  
Quantum Chemical ◽  
Continuum Model ◽  
Polarizable Continuum Model ◽  
Heuristic Approach ◽  
Continuum Models ◽  
Quantum Chemical Approach ◽  
Polarizable Continuum

A simple model based on a quantum chemical approach with polarizable continuum models (PCMs) to provide reasonable translational and rotational entropies for liquid phase molecules was developed.

scholarly journals Н-комплексы 1,2-нафтохинона с молекулами воды в водном растворе и их влияние на сдвиги полос поглощения

2021 ◽  
Vol 129 (5) ◽  
pp. 599
Author(s):  
С.Н. Цеплина ◽  
E.E. Цеплин
Keyword(s):  
Quantum Chemical ◽  
Continuum Model ◽  
Density Functional ◽  
Water Solution ◽  
Polarizable Continuum Model ◽  
Water Molecules ◽  
Absorption Bands ◽  
Functional Theory ◽  
Polarizable Continuum ◽  
Polar Water

Optical absorption spectra of 1,2-naphthoquinone in non-polar (n-hexane) and polar (water) solvents were obtained. It is shown that the use of quantum chemical calculations based on time-dependent density functional theory (TDDFT B3LYP/6-311+G(d, p)) with the polarizable continuum model (PCM) for calculating 1,2-naphthoquinone in a solution of n-hexane and hydrogen complex of 1,2-naphthoquinone with two water molecules in an aqueous medium describes well the shifts of the absorption bands of 1,2-naphthoquinone in a water solution compared to a solution in n-hexane. Based on the analysis of deviations of the calculated band shifts from the experimental ones, the question of the formation of 1,2-naphthoquinone hydrogen complexes with n water molecules (n = 1-4) in an aqueous solution is considered.

Jones and magnetoelectric birefringence of pure substances — A computational study

2009 ◽  
Vol 87 (10) ◽  
pp. 1352-1361 ◽  
Author(s):  
Antonio Rizzo ◽  
Dmitry Shcherbin ◽  
Kenneth Ruud
Keyword(s):  
Condensed Phase ◽  
Continuum Model ◽  
Density Functional ◽  
Computational Study ◽  
Polarizable Continuum Model ◽  
Solvent Interactions ◽  
Dipolar Molecules ◽  
Upper Limits ◽  
Order Of Magnitude ◽  
Polarizable Continuum

We present the first investigation of condensed-phase effects on the Jones (and magnetoelectric) birefringence of a set of nondipolar (CCl4 and CS2) and dipolar (nitro- and chloro-benzene) molecules using a recent implementation of the polarizable continuum model for cubic response functions at the time-dependent density-functional level of theory. The condensed-phase calculations have been performed on the neat liquids of the sample molecules using a nonequilibrium solvation scheme to properly account for the solute–solvent interactions in the presence of a frequency-dependent electromagnetic field. It is demonstrated that the condensed-phase effects as modelled by the polarizable continuum model can be substantial, increasing the observable birefringence by more than sixty percent in the case of CCl4, and by a factor of more than three for CS2. Solvent effects are also substantial for the dipolar molecules, leading to an enhancement by a factor of roughly five for nitrobenzene and by a bit less than 30% for chlorobenzene. Comparison is made with the results of experiment. Our calculated anisotropies confirm that the effect is below current experimental detection limits for CCl4 and CS2. We compute Jones constants of the same order of magnitude as the upper limits given in experiment for nitro- and chlorobenzene.

THEORETICAL STUDY ON HYDROLYSIS MECHANISM OF β-PHOSPHOLACTAMS

2006 ◽  
Vol 05 (spec01) ◽  
pp. 421-431 ◽  
Author(s):  
LINGJUAN YU ◽  
DACHENG FENG ◽  
MAOXIA HE ◽  
RUI LI ◽  
ZHENGTING CAI
Keyword(s):  
Quantum Chemical ◽  
Continuum Model ◽  
Chemical Method ◽  
Theoretical Study ◽  
Polarizable Continuum Model ◽  
Energy Barriers ◽  
Stepwise Mechanism ◽  
Hydrolysis Mechanism ◽  
Polarizable Continuum ◽  
Hydrolysis Of

The neutral hydrolysis mechanisms of a simple β-phospholactam with and without water-assisted reaction have been studied by using quantum chemical method at HF/6-31G**, MP2/6-31G** and B3LYP/6-31G** levels, respectively. The reaction can proceed by two different mechanisms: concerted and stepwise. There are two pathways in stepwise, i.e. pathway a and b, and the energy barriers of them are close. The energy barriers of water-assisted hydrolysis of β-phospholactam are obviously lower than those of no-water-assisted hydrolysis system. The energy barriers of stepwise mechanism are much lower than those of the concerted pathway in both cases. The solvent effects have been considered by means of a polarizable continuum model. The hydrolysis mechanism of β-phospholactam with that of the β-lactam and β-sultam was compared.

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