XZP + 1d and XZP + 1d-DKH basis sets for second-row elements: application to CCSD(T) zero-point vibrational energy and atomization energy calculations

2012 ◽  
Vol 18 (9) ◽  
pp. 4081-4088 ◽  
Author(s):  
Cesar T. Campos ◽  
Francisco E. Jorge ◽  
Júlia M. A. Alves
Keyword(s):  
Vibrational Energy ◽  
Zero Point ◽  
Atomization Energy ◽  
Basis Sets ◽  
Energy Calculations ◽  
Zero Point Vibrational Energy

Ab initio Studies on Hydrazines: 4H-1,2,4-Triazol-4-amine

1989 ◽  
Vol 42 (10) ◽  
pp. 1623 ◽  
Author(s):  
NV Riggs
Keyword(s):  
Saddle Point ◽  
Relative Intensity ◽  
Vibrational Energy ◽  
Zero Point ◽  
Equilibrium Structure ◽  
Vibrational Frequencies ◽  
Basis Sets ◽  
Transition Structure ◽  
Intensity Pattern ◽  
Zero Point Vibrational Energy

The geometries of four stationary structures of 4H-1,2,4-triazol-4-amine have been optimized with the 3-21g and 3-21g(N*) basis sets. The lowest-energy and only equilibrium structure predicted by these calculations is the 'perpendicular' CS form (7). All its calculated vibrational frequencies are real and, after zero-point vibrational-energy corrections, it lies 26.9 kJ mol-1 below the 'parallel' C, structure (6), here characterized as the transition structure for internal rotation about the N-NH2 bond (cf. 26.5 kJ mol-1 for the corresponding structures of 1H-pyrrol-1-amine, but only 8.7 kJ mol-1 for the corresponding structures of 2H-1,2,3-triazol-2-amine). The transition structure for inversion at the NH2 centre is, as for 1H-pyrrol-1-amine and 2H-1,2,3-triazol-2-amine, the perpendicular C2v � structure (5), the barrier being 21.4 kJ mol-1 (cf. 24-26 kJ mol-1 for the two reference azolamines ). The planar C2v structure (4) is a second-order saddle point lying 66.6 kJ mol-1 above the equilibrium structure (cf. 69.4 kJ mol-1 for 1H-pyrrol-1-amine, but only 41 .7 kJ mol-1 for 2H-1,2,3-triazol-2-amine). The calculated NH-stretching vibrational frequencies for 4H-1,2,4-triazol-4-amine are c. 20 cm-1 higher than those of 1H-pyrrol-1-amine and their splitting is c. 8 cm-1 greater but they show a very similar relative-intensity pattern, quite unlike that calculated for 2H-1,2,3-triazol-2-amine. ′

Ab initio Studies on Hydrazines: 1H-Pyrrol-1-amine (N-Aminopyrrole)

1988 ◽  
Vol 41 (3) ◽  
pp. 397 ◽  
Author(s):  
NV Riggs ◽  
L Radom
Keyword(s):  
Saddle Point ◽  
Ab Initio ◽  
Pyrrole Ring ◽  
Vibrational Energy ◽  
Zero Point ◽  
Equilibrium Structure ◽  
Basis Sets ◽  
Primary Amines ◽  
Transition Structure ◽  
Zero Point Vibrational Energy

The geometries of four stationary structures of 1H-pyrrol-1-amine have been optimized with the 3-21G and 3-21G(N*) basis sets. The lowest- energy and only equilibrium structure is the 'perpendicular' CS form (4) in which a pyramidal NH2 group is bisected by the plane of the pyrrole ring. The transition structure for inversion at the NH2 group is the perpendicular C2V form (2). After zero-point vibrational -energy corrections, it lies 24.5 kJ mol-1 [3-21G(N*)] above (4). The transition structure for rotation about the N-NH2 bond is the 'parallel' CS form (3) in which a plane of symmetry bisects both the pyrrole ring and the attached pyramidal NH2 group; it lies 26.5 kJ mol-1 above (4). The planar C2V structure (1) is a second-order saddle point lying 69.4 kJ mol-1 above (4). The spacing of NH-stretching frequencies calculated for the equilibrium structure (4) of 1H-pyrrol-1-amine is in the range for normal primary amines, unlike that for 1,1-dimethylhydrazine.

ON THE NECKING-IN PROCESS IN CLUSTER DECAYS

1990 ◽  
Vol 05 (20) ◽  
pp. 3901-3928 ◽  
Author(s):  
K. DEPTA ◽  
J. A. MARUHN ◽  
HOU-JI WANG ◽  
A. SĂNDULESCU ◽  
W. GREINER ◽  
...  
Keyword(s):  
Potential Energy Surfaces ◽  
Vibrational Energy ◽  
Correction Term ◽  
Zero Point ◽  
Alpha Decay ◽  
Shell Correction ◽  
Macroscopic Models ◽  
Excellent Description ◽  
Energy Surfaces ◽  
Zero Point Vibrational Energy

Two new macroscopic models (liquid drop and Yukawa-plus-exponential) describing the decays with emission of large fragments including alpha decay are developed. The proposed shape parametrization consists of two intersecting spheres smoothly joined by a third "rolling sphere". The first two spheres describe asymptotically the charge and mass asymmetries and the third one the necking-in process. It is shown that the potential energy surfaces in the neck and the relative distance between the centers of the spheres (for a given mass and charge fragmentation) lead to different dynamical paths depending on the mass and charge of the emitted fragment. Along the path a phenomenological shell correction term and a zero point vibrational energy are introduced. It is shown that this model gives an excellent description of the present experimental data.

Zero-point vibrational energy of an adsorbed film

1991 ◽  
Vol 84 (1-2) ◽  
pp. 1-17 ◽  
Author(s):  
James F. Annett ◽  
Milton W. Cole ◽  
Peter B. Shaw ◽  
Richard M. Stratt
Keyword(s):  
Vibrational Energy ◽  
Zero Point ◽  
Adsorbed Film ◽  
Zero Point Vibrational Energy

An Accurate Theoretical Prediction of the Zero Point Vibrational Energy of CH5+

2004 ◽  
Vol 108 (23) ◽  
pp. 4995-4997 ◽  
Author(s):  
Alexey L. Kaledin ◽  
Sharif D. Kunikeev ◽  
Howard S. Taylor
Keyword(s):  
Theoretical Prediction ◽  
Vibrational Energy ◽  
Zero Point ◽  
Zero Point Vibrational Energy

Determination of the Absolute Configuration of 1,5-Diaza-cis-decalin by Comparison of Measured and Calculated CD-Spectra

1998 ◽  
Vol 53 (10-11) ◽  
pp. 896-902 ◽  
Author(s):  
Jörg Fleischhauer ◽  
Gerhard Raabe ◽  
A. G. Santos ◽  
Jan Schiffer ◽  
Axel Wollmer
Keyword(s):  
Absolute Configuration ◽  
Vibrational Energy ◽  
Zero Point ◽  
Equilibrium Mixture ◽  
Cotton Effect ◽  
Basis Set ◽  
Basis Sets ◽  
Cd Spectra ◽  
The Absolute

Abstract The absolute configurations of both 1,5-diaza-c/s-decalin enantiomers were determined by com-parison of measured and calculated CD spectra.CD spectra for both enantiomers were recorded. Theoretical CD spectra for one of the isomers were calculated by means of the semiempirical CNDO/2S method. Eight local minima on the energy hypersurface of the title compound were used to describe the conformer equilibrium mixture. The geometries of these conformers were calculated employing one-determinant ab initio calculations using the split valence 6-31G* basis set. Boltzmann factors were then obtained using relative energies calculated with three different basis sets and including correlation(MP2)-and zero point vibrational energy.Comparing the sign of the observed and calculated longest wavelength Cotton effect, we assign an absolute configuration to the compound. This assignment was verified by means of X-ray structure determination of one of the enantiomers’ α-methoxy-α-trifluoromethylphenyl aceticacid (MTPA, Mosher’s reagent) derivative.

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