The Relative Orientation of the Total Dipole Moment in the N-cis Lone-Electron-Pair-Trans Isomer of Allylamine

1980 ◽  
Vol 35 (4) ◽  
pp. 415-417 ◽  
Author(s):  
Edmund Fischer ◽  
Ivan Botskor
Keyword(s):  
Dipole Moment ◽  
Trans Isomer ◽  
Large Amplitude ◽  
Lone Electron Pair ◽  
Electron Pair ◽  
Dipole Moments ◽  
Relative Orientation ◽  
Total Dipole Moment ◽  
Principal Axes ◽  
Large Amplitude Motions

Abstract The dipole moment of the doubly deuterated species (CH2=CH-CH2-ND2) of N-cis Lone-electron-pair isomer of allylamine has been measured. The "isotope pulling elfect" has been used to determine the relative orientation of the total dipole moment with respect to the principal axes in the normal species. The possible effects of large amplitude motions on the observed effective dipole moments are discussed.

Dipole moments of hydroxamic acids and N,O-diacylhydroxylamines

1981 ◽  
Vol 46 (3) ◽  
pp. 729-739 ◽  
Author(s):  
Aleksandr I. Artemenko ◽  
Inga V. Tikunova ◽  
Evgenii K. Anufriev ◽  
Václav Jehlička ◽  
Otto Exner
Keyword(s):  
Hydrogen Bond ◽  
Dipole Moment ◽  
Intramolecular Hydrogen Bond ◽  
Dipole Moments ◽  
Hydroxamic Acids ◽  
The Other ◽  
Total Dipole Moment ◽  
Statistical Population ◽  
Intramolecular Hydrogen ◽  
Peroxy Acids

Dipole moments of nine aromatic hydroxamic acids Ia-Ii and of nine N,O-diacylhydroxylamines IIa-IIi were measured in dioxan solution. The results for hydroxamic acids are interpreted in terms of the Zsp conformation (A) with an intramolecular hydrogen bond contributing considerably to the total dipole moment; the conformation is similar to that of peroxy acids but the hydrogen bond is weaker. A similar interpretation is possible for N-phenylbenzhydroxamic acids using the dipole moment data from the literature. New data for N,O-diacylhydroxylamine agree with the previously established nonplanar conformation (L). If axially unsymetrical aryl groups are present, they take one of the two coplanar positions independently of the other moiety; hence the effective dipole moments do not differ too much from the assumption of a statistical population of all conformations.

Rotational Isomerism and the Orientation of the Total Dipole Moment

1980 ◽  
Vol 35 (7) ◽  
pp. 748-756 ◽  
Author(s):  
Ivan Botskor
Keyword(s):  
Experimental Data ◽  
Dipole Moment ◽  
Gas Phase ◽  
Dipole Moments ◽  
Microwave Spectroscopy ◽  
Rotational Isomerism ◽  
Total Dipole Moment

A method for determining the orientation of the total dipole moments of distinct rotamers of the same molecule is discussed. Utilizing solely the experimental dipole moments obtained with microwave spectroscopy (gas phase) and an approximate structure, the orientation of the dipole moment can often be determined without use of bond moment considerations. Experimental data from nine rotamer pairs are analyzed to illustrate the method.

The gauche effect on conformation. α-Substituted sulfones and N-substituted sulfonamides

1979 ◽  
Vol 44 (11) ◽  
pp. 3378-3384 ◽  
Author(s):  
Otto Exner ◽  
Jan B. F. N. Engberts
Keyword(s):  
Lone Electron Pair ◽  
Electron Pair ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Conformational Preference ◽  
Electron Pairs ◽  
Gauche Effect

The dipole moments of α-halogenosulfones IIa-f in benzene solution revealed the conformation C, those of N-methyl-N-nitrosulfonamides IIIa-c the conformation F. In either case the conformational preference is governed by the gauche rule which may be worded in a modified version that symmetrical positions of polar bonds and/or of lone electron pairs are disfavoured. A lone electron pair appears to be more significant than a polar bond.

Structure, dipole moment and large amplitude motions of 1-benzofuran

2005 ◽  
Vol 7 (18) ◽  
pp. 3317 ◽  
Author(s):  
Assimo Maris ◽  
B. Michela Giuliano ◽  
Sonia Melandri ◽  
Paolo Ottaviani ◽  
Walther Caminati ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Large Amplitude ◽  
Large Amplitude Motions

Energies and Electric Dipole Moments of the Bound Vibrational States of HN2+ and DN2+

2008 ◽  
Vol 73 (6-7) ◽  
pp. 873-897 ◽  
Author(s):  
Vladimír Špirko ◽  
Ota Bludský ◽  
Wolfgang P. Kraemer
Keyword(s):  
Dipole Moment ◽  
Nearest Neighbor ◽  
Energy Surface ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Vibrational States ◽  
Spacing Distribution ◽  
Triatomic Molecules ◽  
Vibrational Levels ◽  
Different Levels

The adiabatic three-dimensional potential energy surface and the corresponding dipole moment surface describing the ground electronic state of HN2+ (Χ1Σ+) are calculated at different levels of ab initio theory. The calculations cover the entire bound part of the potential up to its lowest dissociation channel including the isomerization barrier. Energies of all bound vibrational and low-lying ro-vibrational levels are determined in a fully variational procedure using the Suttcliffe-Tennyson Hamiltonian for triatomic molecules. They are in close agreement with the available experimental numbers. From the dipole moment function effective dipoles and transition moments are obtained for all the calculated vibrational and ro-vibrational states. Statistical tools such as the density of states or the nearest-neighbor level spacing distribution (NNSD) are applied to describe and analyse general patterns and characteristics of the energy and dipole results calculated for the massively large number of states of the strongly bound HN2+ ion and its deuterated isotopomer.

scholarly journals Understanding (coupled) large amplitude motions: the interplay of microwave spectroscopy, spectral modeling, and quantum chemistry

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ha Vinh Lam Nguyen ◽  
Isabelle Kleiner
Keyword(s):  
Fourier Transform ◽  
Quantum Chemistry ◽  
Large Amplitude ◽  
Environmental Chemistry ◽  
Broad Band ◽  
Microwave Spectroscopy ◽  
Rotational Spectrum ◽  
Spectral Modeling ◽  
Rotational Spectra ◽  
Large Amplitude Motions

AbstractA large variety of molecules contain large amplitude motions (LAMs), inter alia internal rotation and inversion tunneling, resulting in tunneling splittings in their rotational spectrum. We will present the modern strategy to study LAMs using a combination of molecular jet Fourier transform microwave spectroscopy, spectral modeling, and quantum chemical calculations to characterize such systems by the analysis of their rotational spectra. This interplay is particularly successful in decoding complex spectra revealing LAMs and providing reference data for fundamental physics, astrochemistry, atmospheric/environmental chemistry and analytics, or fundamental researches in physical chemistry. Addressing experimental key aspects, a brief presentation on the two most popular types of state-of-the-art Fourier transform microwave spectrometer technology, i.e., pulsed supersonic jet expansion–based spectrometers employing narrow-band pulse or broad-band chirp excitation, will be given first. Secondly, the use of quantum chemistry as a supporting tool for rotational spectroscopy will be discussed with emphasis on conformational analysis. Several computer codes for fitting rotational spectra exhibiting fine structure arising from LAMs are discussed with their advantages and drawbacks. Furthermore, a number of examples will provide an overview on the wealth of information that can be drawn from the rotational spectra, leading to new insights into the molecular structure and dynamics. The focus will be on the interpretation of potential barriers and how LAMs can act as sensors within molecules to help us understand the molecular behavior in the laboratory and nature.

scholarly journals DERIVATION OF GENERALIZED THOMAS–BARGMANN–MICHEL–TELEGDI EQUATION FOR A PARTICLE WITH ELECTRIC DIPOLE MOMENT

2013 ◽  
Vol 28 (29) ◽  
pp. 1350147 ◽  
Author(s):  
TAKESHI FUKUYAMA ◽  
ALEXANDER J. SILENKO
Keyword(s):  
Dipole Moment ◽  
Electromagnetic Fields ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Dipole Moments ◽  
Classical Equation ◽  
Spin Motion ◽  
Electric Dipole Moments ◽  
Momentum Direction ◽  
Telegdi Equation

General classical equation of spin motion is explicitly derived for a particle with magnetic and electric dipole moments in electromagnetic fields. Equation describing the spin motion relative to the momentum direction in storage rings is also obtained.

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