Comparison of large basis set DFT and MP2 calculations in the study of the barrier for internal rotation of 2,3,5,6-tetrafluoroanisole

2006 ◽  
Vol 107 (2) ◽  
pp. 403-417 ◽  
Author(s):  
Martina Kieninger ◽  
Raúl E. Cachau ◽  
Heinz Oberhammer ◽  
Oscar N. Ventura
Keyword(s):  
Internal Rotation ◽  
Basis Set ◽  
Mp2 Calculations ◽  
Dft And Mp2 Calculations

scholarly journals Exhaustive exploration of the conformational landscape of mono- and disubstituted five-membered rings by DFT and MP2 calculations

RSC Advances ◽  
2019 ◽  
Vol 9 (42) ◽  
pp. 24134-24145 ◽  
Author(s):  
Carlos A. Stortz ◽  
Ariel M. Sarotti
Keyword(s):  
Ab Initio ◽  
Membered Ring ◽  
Basis Set ◽  
Mp2 Calculations ◽  
Conformational Landscape ◽  
Dft And Mp2 Calculations

The conformational landscape of 22 different non, mono-, and disubstituted compounds with a five-membered ring was thoroughly explored by ab initio (MP2) and DFT (B3LYP and M06-2X) methods with the 6-311+G** basis set.

DFT and MP2 calculations on new series of hydroxythioxanthones

2013 ◽  
Vol 1039 ◽  
pp. 8-21 ◽  
Author(s):  
Alireza Salimi Beni ◽  
Setareh Mirzaei Monfared
Keyword(s):  
Mp2 Calculations ◽  
Dft And Mp2 Calculations

The influence of basis set on the ab initio prediction of internal rotation barrier heights in ethene thiol

1992 ◽  
Vol 3 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Christopher Plant ◽  
James E. Boggs ◽  
John N. Macdonald ◽  
Gwilym A. Williams
Keyword(s):  
Ab Initio ◽  
Internal Rotation ◽  
Basis Set ◽  
Rotation Barrier ◽  
Barrier Heights ◽  
Ab Initio Prediction ◽  
Internal Rotation Barrier

DFT and MP2 Calculations on Tautomers and Water-Assisted Proton Transfer on 1,2,5-Oxadiazol-4,3-diamine

2018 ◽  
Vol 92 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Alireza Salimi Beni ◽  
Maryam Zarandi ◽  
Akram Hashemi ◽  
Behzad Hosseinzadeh ◽  
Alireza Najafi Chermahini
Keyword(s):  
Proton Transfer ◽  
Mp2 Calculations ◽  
Dft And Mp2 Calculations

Ab initio Studies of Hydrazines: Equilibrium Structures of 1,1-Dimethylhydrazine and Transition Structures Connecting Them

1987 ◽  
Vol 40 (11) ◽  
pp. 1783 ◽  
Author(s):  
NV Riggs ◽  
L Radom
Keyword(s):  
Internal Rotation ◽  
Vibrational Energy ◽  
Zero Point ◽  
Basis Set ◽  
Basis Sets ◽  
Primary Amines ◽  
Rotational Angle ◽  
Small Rise ◽  
Equilibrium Structures ◽  
Anti Form

Optimization of the geometries of various stationary structures of 1,1-dimethylhydrazine has been carried out with the 3-21G and 3-21G(N*) basis sets, and the energies of each of the latter optimized structures have been evaluated with the 6.31G* basis set. The gauche form with a (mean) internal rotational angle near 80� (hydrazine, approx. 90�) is the lowest-energy form. After zero-point vibrational -energy corrections, the anti form lies in a shallow well 14kJ mol-1 higher on the potential-energy surface for internal rotation, and the transition structure connecting them lies approx. 1 kJ mol-1 higher still. The anti form is thus a true equilibrium species, unlike the case for hydrazine, but constitutes less than 0.5% of the molecules present at room temperature. It is estimated to have a half-life of less than 10 ps , so its observation by present physical methods may prove to be difficult. The barrier to internal rotation via the syn form (41kJ mol-1) coincides with that for hydrazine. gem-Dimethyl substitution in hydrazine leads to a small rise (1-2 kJ mol-1) in the barrier to inversion at the unsubstituted nitrogen atom, but to an unexpectedly high (by 8-9 kJ mol-1) calculated barrier to inversion at the substituted centre, whether the result be referred to the barrier in hydrazine or to that in dimethylamine. Calculated NH stretching frequencies for the gauche form show a spacing much larger than that for 'simple' primary amines, as is found experimentally.

scholarly journals Conformational study of isolated pindolol by HF, DFT and MP2 calculations

2007 ◽  
Vol 806 (1-3) ◽  
pp. 231-238 ◽  
Author(s):  
Sandra C.C. Nunes ◽  
A.J. Lopes Jesus ◽  
Mário Túlio S. Rosado ◽  
M. Ermelinda S. Eusébio
Keyword(s):  
Conformational Study ◽  
Mp2 Calculations ◽  
Dft And Mp2 Calculations
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