scholarly journals The torsional states of methyl hydroperoxide molecule calculated using anharmonic zero point vibrational energy

2021 ◽  
pp. 15-24
Author(s):  
George A. Pitsevich ◽  
Alexander E. Malevich ◽  
Uladzimir V. Lazicki ◽  
Uladzimir U. Sapeshka
Keyword(s):  
Dipole Moment ◽  
Potential Energy ◽  
Internal Rotation ◽  
Vibrational Energy ◽  
Theoretical Data ◽  
Zero Point ◽  
Methyl Groups ◽  
Potential Barriers ◽  
Methyl Hydroperoxide ◽  
Zero Point Vibrational Energy

The 2D surfaces of potential energy, kinematic coefficients, components of the dipole moment, the heights of potential barriers, the energies of stationary torsional states, and the tunneling frequencies of hydroxyl and methyl groups in the methyl hydroperoxide molecule were calculated at MP2/CBS and CCSD(T)/Aug-cc-pVTZ levels of theory. Additionally, calculations of the 2D surface of zero point vibrational energy of the molecule in the harmonic and anharmonic approximations were performed at MP2/Aug-cc-pVTZ level of theory. The zero point vibrational energy calculated in two approximations is summed up with the potential energy of the methyl hydroperoxide molecule, calculated at two levels of theory, and the resulting four outcomes of the refined potential energy are used to calculate the energies of stationary torsional states and tunneling frequencies. The results obtained are compared with the experimental and theoretical data presented in the literature to evaluate the efficiency of taking into account the zero point vibrational energy when examining the internal rotation in molecules.

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

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.

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