Theoretical Study of H(D) + N2O: Effects of Pressure, Temperature, and Quantum-Mechanical Tunneling on H(D)-Atom Decay and OH(D)-Radical Production

1995 ◽  
Vol 99 (17) ◽  
pp. 6589-6594 ◽  
Author(s):  
Eric W. G. Diau ◽  
M. C. Lin
Keyword(s):  
Theoretical Study ◽  
Quantum Mechanical ◽  
Quantum Mechanical Tunneling ◽  
Radical Production ◽  
Atom Decay

Spin-forbidden heavy-atom tunneling in the ring-closure of triplet cyclopentane-1,3-diyl

2021 ◽  
Author(s):  
Luís P. Viegas ◽  
Cláudio Manaia Nunes ◽  
Rui Fausto
Keyword(s):  
Heavy Atom ◽  
Ring Closure ◽  
Quantum Mechanical ◽  
Quantum Mechanical Tunneling

In 1975, Buchwalter and Closs reported one of the first examples of heavy-atom quantum mechanical tunneling (QMT) by studying the ring closure of triplet cyclopentane-1,3-diyl to singlet bicyclo[2.1.0]pentane in cryogenic...

scholarly journals Experimental and theoretical study of Aspartic acid

2019 ◽  
Keyword(s):  
Aspartic Acid ◽  
Single Molecule ◽  
Dft Calculation ◽  
Theoretical Study ◽  
Quantum Mechanical ◽  
Experimental Ir ◽  
Vibrational Bands ◽  
Computational Research ◽  
Ir And Raman ◽  
Dielectric Environment

The aim of this research is to detect zwittterionic structure of the aspartic acid and confirm the experimental spectra with quantum chemical calculations. The experimental IR and Raman spectra of aspartic acid powder show no vibrational bands of OH and NH stretching in expected spectral region. We assume that zwitterionic structure of aspartic acid is responsible for lowering the frequencies of these vibrations. An extensive experimental and computational research supports this assumption. Our DFT calculation strongly suggests the need for the dielectric environment in order to stabilize the zwitterionic structure of a single molecule. The network of intermolecular hydrogen bonding between aspartic acid molecules provides this dielectric environment. The DFT quantum mechanical calculations corroborate this assumption by optimizing a four-member group of molecules, which also gives an explanation of broad IR spectrum lines.

scholarly journals Contact Electrification by Quantum-Mechanical Tunneling

Research ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Morten Willatzen ◽  
Zhong Lin Wang
Keyword(s):  
Potential Versus ◽  
Coulomb Repulsion ◽  
Quantum Mechanical ◽  
Quantum Mechanical Tunneling ◽  
One Dimensional ◽  
Contact Electrification ◽  
Order Of Magnitude ◽  
Left And Right ◽  
Tunneling Dynamics ◽  
Vacuum Gap

A simple model of charge transfer by loss-less quantum-mechanical tunneling between two solids is proposed. The model is applicable to electron transport and contact electrification between e.g. a metal and a dielectric solid. Based on a one-dimensional effective-mass Hamiltonian, the tunneling transmission coefficient of electrons through a barrier from one solid to another solid is calculated analytically. The transport rate (current) of electrons is found using the Tsu-Esaki equation and accounting for different Fermi functions of the two solids. We show that the tunneling dynamics is very sensitive to the vacuum potential versus the two solids conduction-band edges and the thickness of the vacuum gap. The relevant time constants for tunneling and contact electrification, relevant for triboelectricity, can vary over several orders of magnitude when the vacuum gap changes by one order of magnitude, say, 1 Å to 10 Å. Coulomb repulsion between electrons on the left and right material surfaces is accounted for in the tunneling dynamics.

Quantum mechanical versus quasi-classical tunneling times for smooth potential barriers

2003 ◽  
Vol 81 (3) ◽  
pp. 573-581 ◽  
Author(s):  
M R.A. Shegelski ◽  
E V Kozijn
Keyword(s):  
Quantum Mechanical ◽  
Tunneling Time ◽  
Quantum Mechanical Tunneling ◽  
Potential Barriers ◽  
Smooth Potential ◽  
Tunneling Times

For smooth potential barriers, we compare the quasi-classical tunneling time with an expression that gives a fully quantum mechanical tunneling time. The expression we choose for the quantum mechanical tunneling time is one that has heuristic value. We report results wherein this quantum mechanical tunneling time and the quasi-classical time differ significantly, both quantitatively and qualitatively. To determine the reasons for these differences, we compare the trends in the two times that result from varying the potential. Our findings suggest that, for smooth potential barriers, the quasi-classical tunneling time is unreliable for many cases where it is employed. PACS Nos.: 03.65Xp, 03.65-w

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