scholarly journals Hydrogen Delocalization in an Asymmetric Biomolecule: The Curious Case of Alpha-Fenchol

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 101
Author(s):  
Robert Medel ◽  
Johann R. Springborn ◽  
Deborah L. Crittenden ◽  
Martin A. Suhm
Keyword(s):  
Hydrogen Atom ◽  
Quantum Tunneling ◽  
Global Minimum ◽  
Propargyl Alcohol ◽  
The Third ◽  
Spectroscopy Studies ◽  
Computational Predictions

Rotational microwave jet spectroscopy studies of the monoterpenol α-fenchol have so far failed to identify its second most stable torsional conformer, despite computational predictions that it is only very slightly higher in energy than the global minimum. Vibrational FTIR and Raman jet spectroscopy investigations reveal unusually complex OH and OD stretching spectra compared to other alcohols. Via modeling of the torsional states, observed spectral splittings are explained by delocalization of the hydroxy hydrogen atom through quantum tunneling between the two non-equivalent but accidentally near-degenerate conformers separated by a low and narrow barrier. The energy differences between the torsional states are determined to be only 16(1) and 7(1) cm−1hc for the protiated and deuterated alcohol, respectively, which further shrink to 9(1) and 3(1) cm−1hc upon OH or OD stretch excitation. Comparisons are made with the more strongly asymmetric monoterpenols borneol and isopinocampheol as well as with the symmetric, rapidly tunneling propargyl alcohol. In addition, the third—in contrast localized—torsional conformer and the most stable dimer are assigned for α-fenchol, as well as the two most stable dimers for propargyl alcohol.

scholarly journals Hydrogen Delocalization in an Asymmetric Biomolecule: The Curious Case of alpha-Fenchol

2021 ◽  
Author(s):  
Robert Medel ◽  
Johann R. Springborn ◽  
Deborah L. Crittenden ◽  
Martin A. Suhm
Keyword(s):  
Hydrogen Atom ◽  
Quantum Tunneling ◽  
Propargyl Alcohol ◽  
Stable Conformer ◽  
The Third ◽  
Spectroscopy Studies ◽  
Computational Predictions

Rotational microwave jet spectroscopy studies of the monoterpenol α-fenchol have so far failed to identify its second expected torsional conformer, despite computational predictions that it is only very slightly higher in energy than the most stable conformer. Vibrational FTIR and Raman jet spectroscopy investigations reveal unusually complex OH and OD stretching spectra compared to other alcohols. Via modelling of the torsional states, observed spectral splittings are explained by delocalization of the hydroxy hydrogen atom through quantum tunneling between the two non-equivalent but accidentally near-degenerate conformers separated by a low and narrow barrier. The energy differences between the torsional states are determined to be only 16(1) and 7(1) cm$^{−1}hc$ for the protiated and deuterated alcohol, respectively, which further shrink to 9(1) and 3(1) cm$^{−1}hc$ upon OH or OD stretch excitation. Comparisons are made with the more strongly asymmetric monoterpenols borneol and isopinocampheol as well as with the symmetric, rapidly tunneling propargyl alcohol. Assigned are also for α-fenchol the third – in contrast localized – torsional conformer and the most stable dimer, as well as for propargyl alcohol the two most stable dimers.

Schrödinger’s Derivation of the Wave Equation

2020 ◽  
pp. 89-110
Author(s):  
Jim Baggott
Keyword(s):  
Wave Equation ◽  
Hydrogen Atom ◽  
Wave Motion ◽  
Classical Equation ◽  
Erwin Schrödinger ◽  
Quantum Numbers ◽  
Vibrating String ◽  
Spectroscopy Studies ◽  
Phd Thesis ◽  
Natural Way

Bohr’s theory of the atom was in trouble as soon as it was formulated. Further detailed spectroscopy studies encouraged a proliferation of quantum numbers and ‘selection rules’ in what became known as the Bohr–Sommerfeld model. It couldn’t last, and by 1925 the theory was in crisis. The immediate concern was with the quantum numbers themselves. Where did they come from? Could de Broglie’s hypothesis shed any light? In October 1925 the attentions of Erwin Schrödinger were drawn to a footnote in one of Einstein’s recent papers. Intrigued, Schrödinger acquired a copy of de Broglie’s PhD thesis. Although he eventually published a more obscure derivation, Schrödinger essentially applied the de Broglie relation to the classical equation of wave motion. He applied the result to the hydrogen atom, and showed that the quantum numbers emerge ‘in the same natural way as the integers specifying the number of nodes in a vibrating string’.

Quantum Tunneling of Hydrogen Atom in Dissociation of Photoexcited Methylamine†

2010 ◽  
Vol 114 (36) ◽  
pp. 9623-9627 ◽  
Author(s):  
Ran Marom ◽  
Chen Levi ◽  
Tal Weiss ◽  
Salman Rosenwaks ◽  
Yehuda Zeiri ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Quantum Tunneling

scholarly journals Quantum tunneling of hydrogen atom transfer affects mandrel degradation in ICF target fabrication

iScience ◽  
2021 ◽  
pp. 103674
Author(s):  
Yu Zhu ◽  
Xinrui Yang ◽  
Famin Yu ◽  
Rui Wang ◽  
Qiang Chen ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Quantum Tunneling ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Icf Target

Progress report on 21-cm observations at low latitude between longitudes (l 11) 0° and 66°

1967 ◽  
Vol 31 ◽  
pp. 177-179
Author(s):  
W. W. Shane
Keyword(s):  
Preliminary Report ◽  
Progress Report ◽  
Galactic Centre ◽  
Low Latitude ◽  
The Third ◽  
Introductory Lecture ◽  
Centre Region

In the course of several 21-cm observing programmes being carried out by the Leiden Observatory with the 25-meter telescope at Dwingeloo, a fairly complete, though inhomogeneous, survey of the regionl11= 0° to 66° at low galactic latitudes is becoming available. The essential data on this survey are presented in Table 1. Oort (1967) has given a preliminary report on the first and third investigations. The third is discussed briefly by Kerr in his introductory lecture on the galactic centre region (Paper 42). Burton (1966) has published provisional results of the fifth investigation, and I have discussed the sixth in Paper 19. All of the observations listed in the table have been completed, but we plan to extend investigation 3 to a much finer grid of positions.

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