Gas-phase properties and Fukui indices of sulfine (CH 2 SO). Potential energy surface and maximum hardness principle for its protonation process. A density functional study

1999 ◽  
Vol 101 (6) ◽  
pp. 388-395 ◽  
Author(s):  
T. Mineva ◽  
N. Russo ◽  
E. Sicilia ◽  
M. Toscano
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Surface ◽  
Functional Study ◽  
Maximum Hardness ◽  
Density Functional Study ◽  
Fukui Indices ◽  
Maximum Hardness Principle

scholarly journals Potential Energy Surface (PES) Scan of Gas-Phase L-Proline

2014 ◽  
Vol 38 ◽  
pp. 26-34
Author(s):  
Anouar el Guerdaoui ◽  
Yassine el Kahoui ◽  
Malika Bourjila ◽  
Rachida Tijar ◽  
Abderrahman el Gridani
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Gas Phase ◽  
Density Functional ◽  
Energy Surface ◽  
Conformational Stability ◽  
Geometry Optimization ◽  
Basis Set ◽  
Absolute Minimum ◽  
Pes Scan

We performed here a systematic ab initio calculations on neutral gas-phase L-proline. A total of 8 local minima were located by geometry optimization of the trial structures using density functional theory (DFT) with B3LYP three parameter hybrid potential coupled with the 6-31G)d( basis set. The absolute minimum obtained will be subject to a rigid potential energy surface (PES) scan by rotating its carboxylic group using the same method with more accurate basis set B3LYP/6-311++G(d,p), to get a deeper idea about its conformational stability. The main aim of the present work was the study of the rigidity of the L-proline structure and the puckering of its pyrrolidine ring.

scholarly journals HEAT OF HYDRATION OF DIETHYLSULFONE BY QUANTUM CHEMICAL CALCULATION

2018 ◽  
Vol 61 (8) ◽  
pp. 17
Author(s):  
Ashot S. Mkhitaryan ◽  
Zakar K. Papanyan ◽  
Liana S. Gabrielyan ◽  
Shiraz A. Markarian
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Density Functional ◽  
Energy Surface ◽  
Average Energy ◽  
Functional Theory ◽  
The Density Functional Theory

The quantum chemical study of the hydration of diethyl sulfone was performed by using Gaussian 09 software package. The conformational analysis of the isolated molecule of diethyl sulfone is performed by the restricted Hartree-Fock (RHF) and the density functional theory (DFT/B3PW91) methods with 6-311++G(d,p) extended basis set. The analysis of the potential energy surface revealed the existence of four stable conformers of diethyl sulfone with different degrees of degeneracy. The nature of stationary points on the potential energy surface is verified by the complete gas phase optimization and the vibrational analysis. The global minimum is the conformer with two (CCSC) dihedral angles equal 180°. The fractional population distribution of different conformers is determined by Boltzmann distribution. The average energy of the diethyl sulfone molecule in vacuum is calculated. To account the effect of solvent the self-consistent reaction field (SCRF) method, particularly, solvent model based on electron density (SMD), was employed. It is shown, that solvent affects on the relative population of conformers. The thermodynamic parameters, in particular enthalpy, for the conformers of diethyl sulfone are determined both in the gas phase and in the aqueous solution. The average energy of diethyl sulfone in water is calculated. It is shown, that although the dissolution of crystalline diethyl sulfone in water is an endothermic process, the hydration of diethyl sulfone molecules occurs with the release of heat. The heat of dissolution of diethyl sulfone calculated by the density functional theory is consistent with the experimental data.

THE H2NO POTENTIAL ENERGY SURFACE EXPLORED WITH HIGH LEVEL AB INITIO AND DENSITY FUNCTIONAL THEORY METHODS

2007 ◽  
Vol 06 (03) ◽  
pp. 549-562
Author(s):  
ABRAHAM F. JALBOUT
Keyword(s):  
Density Functional Theory ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Density Functional ◽  
Energy Surface ◽  
Hybrid Methods ◽  
Transition States ◽  
Basis Set ◽  
Functional Theory ◽  
High Level

The transition states for the H 2 NO decomposition and rearrangements mechanisms have been explored by the CBS-Q method or by density functional theory. Six transition states were located on the potential energy surface, which were explored with the Quadratic Complete Basis Set (CBS-Q) and Becke's one-parameter density functional hybrid methods. Interesting deviations between the CBS-Q results and the B1LYP density functional theory lead us to believe that further study into this system is necessary. In the efforts to further assess the stabilities of the transition states, bond order calculations were performed to measure the strength of the bonds in the transition state.

Sign in / Sign up

Export Citation Format

Share Document