scholarly journals Screened Range-Separated Hybrid Functional with Polarizable Continuum Model Overcomes Challenges in Describing Triplet Excitations in the Condensed Phase Using TDDFT

2020 ◽  
Vol 16 (5) ◽  
pp. 3287-3293 ◽  
Author(s):  
Khadiza Begam ◽  
Srijana Bhandari ◽  
Buddhadev Maiti ◽  
Barry D. Dunietz
Keyword(s):  
Condensed Phase ◽  
Continuum Model ◽  
Polarizable Continuum Model ◽  
Hybrid Functional ◽  
Polarizable Continuum

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 Raman and Infrared Spectra for Amphetamine, Methamphetamine and 3,4-Methylenedioxymethamphetamine

2020 ◽  
Vol 12 (6) ◽  
pp. 703-710
Author(s):  
Leandro G. Silva ◽  
Abel F. G. Neto ◽  
José F. S. Costa ◽  
Tais S. S. Pereira ◽  
Mozaniel S. Oliveira ◽  
...  
Keyword(s):  
Infrared Spectra ◽  
Continuum Model ◽  
Illicit Drugs ◽  
Normal Modes ◽  
Polarizable Continuum Model ◽  
Program Package ◽  
Basis Set ◽  
Hybrid Functional ◽  
Polarizable Continuum

Molecules used in the synthesis of illicit drugs, such as amphetamine, methamphetamine and 3,4-methylenedioxymethamphetamine which were studied in order to provide parameters to do their identification. Thus, Raman and Infrared spectra were calculated taking into account the polarizable continuum model and considering different solvents (water, toluene, acetone, chloroform and ethanol) at 298.15 K and 1 atm. The assignment of the normal modes of vibrations of these molecules was made. All calculations were carried out by quantum methods based on DFT with B3LYP hybrid functional and 6-311++g(d. p) basis set available in the Gaussian G03 program package. These informations can be helpful as a forensic data.

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.

Solvent and temperature effects on the tautomerization of a carbonitrile molecule: A conductor-like polarizable continuum model (CPCM) study

2021 ◽  
Vol 20 (1) ◽  
pp. 59-68
Author(s):  
Zohreh Khanjari ◽  
Bita Mohtat ◽  
Reza Ghiasi ◽  
Hoorieh Djahaniani ◽  
Farahnaz Kargar Behbahani
Keyword(s):  
Gas Phase ◽  
Solvent Effects ◽  
Continuum Model ◽  
Solvent Polarity ◽  
Polarizable Continuum Model ◽  
Dielectric Constants ◽  
Frontier Orbitals ◽  
Reaction Field ◽  
Polarizable Continuum ◽  
Homo Lumo

This research examined the effects of solvent polarity and temperature on the tautomerization of a carbonitrile molecule at CAM-B3LYP/6-311G (d,p) level of theory. The selected solvents were n-hexane, diethyl ether, pyridine, ethanol, methanol, and water. The solvent effects were examined by the self-consistent reaction field theory (SCRF) based on conductor-like polarizable continuum model (CPCM). The solvent effects were explored on the energy barrier, frontier orbitals energies, and HOMO-LUMO gap. Dependencies of thermodynamic parameters (ΔG and ΔH) on the dielectric constants of solvents were also tested. Specifically, the temperature dependencies of the thermodynamics parameters were studied within 100–1000 K range. The rate constant of the tautomerism reaction was computed from 300 to 1200 K, in the gas phase.

THEORETICAL CALCULATION OF pKb VALUES FOR ANILINES AND SULFONAMIDE DRUGS IN AQUEOUS SOLUTION

2012 ◽  
Vol 11 (02) ◽  
pp. 283-295 ◽  
Author(s):  
BAHRAM GHALAMI-CHOOBAR ◽  
ALI GHIAMI-SHOMAMI ◽  
PARIA NIKPARSA
Keyword(s):  
Gas Phase ◽  
Continuum Model ◽  
Correlation Equation ◽  
Polarizable Continuum Model ◽  
Free Energies ◽  
Pcm Model ◽  
Solvation Models ◽  
Polarizable Continuum ◽  
Better Than ◽  
Good Agreement

In this work, calculations of p K b values have been performed for aniline and its substituted derivatives and sulfonamide drugs by using Gaussian 98 software package. Gas-phase energies were calculated with HF /6-31 G ** and B3LYP /6-31 G ** levels of theory. Free energies of solvation have been computed using the polarizable continuum model (PCM), conductor-like polarizable continuum model (CPCM) and the integral equation formalism-polarizable continuum model (IEFPCM) at the same levels which have been used for geometry determination in the gas-phase. The results show that the calculated p K b values using the B3LYP /6-31 G ** are better than those using the corresponding HF /6-31 G **. At first, the correlation equation was found to determine the p K b values of the investigated anilines. Then, this correlation equation was used to calculate the p K b values of the sulfonamide drugs. The results obtained indicate that the PCM model is a suitable solvation model for calculating p K b values in comparison to the other solvation models. For the investigated compounds a good agreement between the experimental and the calculated p K b values was also observed.

A new discretization for the polarizable continuum model within the domain decomposition paradigm

2016 ◽  
Vol 144 (5) ◽  
pp. 054101 ◽  
Author(s):  
Benjamin Stamm ◽  
Eric Cancès ◽  
Filippo Lipparini ◽  
Yvon Maday
Keyword(s):  
Domain Decomposition ◽  
Continuum Model ◽  
Polarizable Continuum Model ◽  
Polarizable Continuum
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