The Molecular 0-Tensor, the Magnetic Susceptibility Anisotropy, and the Molecular Electric Quadrupole Moment Tensor of Monofluoroacetonitrile, a Rotational Zeeman Effect Study

1991 ◽  
Vol 46 (12) ◽  
pp. 1049-1054
Author(s):  
H. Krause ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Moment Tensor ◽  
Zeeman Effect ◽  
Heavy Atom ◽  
Electric Quadrupole ◽  
Effect Study ◽  
Field Calculation ◽  
Quadrupole Moments ◽  
Magnetic Susceptibility Anisotropy ◽  
Magnetic Susceptibility Tensor

Abstract The rotational Zeeman effect of H2F12C12C14N was observed at fields up to 20 kG (2 Tesla). The observed vibronic ground state expectation values for the molecular ^-values, the magnetic susceptibility anisotropies and the molecular electric quadrupole moments, all referred to the molecular principal inertia axes system, are: gaa= -0.03572 (11), gbb= -0.03438 (7), gcc= -0.03988 (6). 2ξaa- ξbb - ξcc = - 14.58 (10) • 10-6 erg/(G2 mole), 2ξaa- ξbb - ξcc= 1.60 (11) • 10-6 erg/(G2 mole), Qaa= -9.13 (6) DÅ, Qbb = 4M (7) DÅ, and Qcc = 4.96 (9) DÅ, respectively. The latter are in close agreement with the results of a restricted Hartree Fock self consistent field calculation with a basis of TZVP quality, which was carried out at the partial restructure determined earlier. Therefore the RHF/TZVP-value for the second electronic moment perpendicular to the heavy atom plane, <0|Σ c2c|0)RHF, was used as additional input to predict the molecular bulk susceptibility and the individual components of the magnetic susceptibility tensor

Molecular Values, Magnetic Susceptibility Anisotropies and Molecular Electric Quadrupole Moments of Difluoroacetonitrile. A Rotational Zeeman Effect Study

1987 ◽  
Vol 42 (2) ◽  
pp. 167-173 ◽  
Author(s):  
J. Spieckermann ◽  
M. Andolfatto ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Effect Study ◽  
Nitrile Group ◽  
Group Comparison ◽  
Quadrupole Moments ◽  
Susceptibility Tensor ◽  
Magnetic Susceptibility Tensor ◽  
Electron Withdrawal

The rotational Zeeman effect of several low J rotational transitions of difluoroacetonitrile has been studied under high resolution conditions with a microwave superheterodyne bridge spectrometer. The observed anisotropies in the molecular magnetic susceptibility tensor are discussed within the model of local susceptibilities to derive the magnetic susceptibility tensor of the nitrile group. Comparison with results obtained earlier for acrylonitrile shows significant changes, probably due to electron withdrawal from the CN-group by the neighbouring fluorine atoms.

scholarly journals The Molecular Zeeman Effect of Imines. I. Methanimine, its Molecular g-Tensor, its Magnetic Susceptibility Anisotropies, its Molecular Electric Quadrupole Moment, its Electric Field Gradient at the Nitrogen Nucleus, and its Nitrogen Spin-Rotation Coupling

1989 ◽  
Vol 44 (11) ◽  
pp. 1063-1078 ◽  
Author(s):  
H. Krause ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Zero Field ◽  
Quadrupole Moments ◽  
Magnetic Susceptibility Tensor ◽  
State Expectation ◽  
The Individual

Abstract The rotational Zeeman effect has been observed in methanimine which was produced from ethylenediamine by flash pyrolysis. The observed vibronic ground state expectation values of the molecular g-values, the magnetic susceptibility anisotropies and the molecular electric quadrupole moments are: gaa = -1.27099(22), gbb= -0.18975(7), gcc= -0.03440(8), 2ξaa-ξbb-ξcc = 12.49(19) · 10-6 ergG-2mol-1, 2ξbb-ξcc-ξaa = 5.22(11) · 10-6 ergG-2 mol-1 Qaa = 0.43(17) · 10-26esu cm2, Qbb= 1.08(10) · 10-26 esu cm2, and Qcc= -1.51 (26) . 10-26 esu cm2. With the TZVP ab initio value for the out-off plane electronic second moment as additional input, reliable values can be given also for the individual components of the magnetic susceptibility tensor and for the bulk susceptibility:ξ = (ξaa + ξbb + ξcc)/3=-13.13(88) · 10-6 erg G -2 mol-1. From low-J a-and b-type zero field transitions the spin-rotation coupling constants and the 14N nuclear quadrupole coupling constants could be redetermined with improved accuracy. These data are compared with our new theoretical results.

The Rotational Zeeman Effect in Acetone, its g-Tensor, its Magnetic Susceptibility Anisotropics and its Molecular Electric Quadrupole Moment Tensor; A High Resolution Microwave Fourier Transform Study

1992 ◽  
Vol 47 (3) ◽  
pp. 527-532 ◽  
Author(s):  
Frank Oldag ◽  
Dieter H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Fourier Transform ◽  
Quadrupole Moment ◽  
Moment Tensor ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Effect Study ◽  
Rigid Rotor ◽  
Electric Quadrupole Moment ◽  
Asymmetric Top

Abstract Acetone is a molecule with an intermediate barrier for methyl- top internal rotation, and only molecules in the A1A1 - state of the tunneling motion exhibit a rigid rotor spectrum. For this state we report the results of a rotational Zeeman effect study of acetone in exterior fields up to 20 kGauss (2 Tesla). From an analysis of the observed Zeeman splittings within the asymmetric top approximation the nonzero elements of the g-tensor and the magnetic susceptibility anisotropies were obtained as follows: gaa= -0.04379 (8), gbb = - 0.06611 (5), gcc=-O.O1481 (7), 2ξaa -ξbb - ξcc = - 9.53 (21) 10-6 erg G -2 mole-1 and 2 ξbb - ξcc - ξaa = 25.57 (18) 10-6 erg G -2 mole-1 . The nonzero elements of the molecular electric quadrupole moment tensor were derived as Qaa- 2-77 (13) DÅ, Qbb= -4.59 (10) DÅ and Qcc= 1.82 (15) DÅ. Zeeman spectra were also recorded for seveal low-J transitions of molecules in the EE-state of methyl top tunneling (one top tunneling), and so far the same splittings have been found as for the A1 A1-species

Nonlocal Susceptibilities and Molecular Electric Quadrupole Moments of 3-Fluoropyridine and 2,6-Difluoropyridine, a Rotational Zeeman Effect Study

1981 ◽  
Vol 36 (4) ◽  
pp. 332-346 ◽  
Author(s):  
D. Hübner ◽  
M. Stolze ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Effect Study ◽  
Quadrupole Moments ◽  
Molecular Plane ◽  
Magnetic Susceptibilities ◽  
Straight Line ◽  
Out Of Plane ◽  
Experimental Values

The rotational Zeeman effect spectra of 3-Fluoropyridine and 2,6-Difluoropyridine have been measured. The molecular g-values are gaa = - 0.0917(5), gbb = - 0.0476(5), gcc = +0.0194(5) for 3-Fluoropyridine and gaa= -0.0573(6), gbb =0.0311(6), gcc =0.0102(6) for 2,6-Difluoro- pyridine. The values for the magnetic susceptibility anisotropics in units of 10-6 erg/(G2 mol) are 2Xaa+Xbb + Xcc = 53.3(8), 2Xbb-Xcc-Xaa = 60.5(7) for 3-Fluoropyridine and 2Xaa-Xbb -Xcc = 48.4(11), 2Xbb-Xcc-Xaa=51.7(11) for 2,6-Difluoropyridine. Subtraction of the local atom contributions to the magnetic susceptibilities indicates that Fluorine quenching of the nonlocal out of plane contribution depends on the position of the substituent. Further, the data suggest a linear correlation between X⟂nonlocal and the “CNDO/2-π-density alternation”, which is used to predict susceptibility anisotropics of Fluorobenzenes and Fluoropyridines not yet measured.The molecular quadrupole moments are calculated from the Zeeman data and compared with the experimental values obtained for various fluorosubstituted Pyridines and Benzenes. If the quadrupole moments perpendicular to the molecular plane are referred to the centers of the six membered rings and are plotted against the number of Fluoroine substituents, nF, the plots closely follow a straight line with identical slopes for the Pyridine- and Benzenefamilies, but with different intercepts at nF = 0. From the “nF = 0 intercept” for the Fluorobenzenes we conclude that the Benzene quadrupole moment proposed earlier by Shoemaker and Flygare should probably be revised

Molecular g-Values, Magnetic Susceptibility Anisotropies, Molecular Quadrupole Moments and the Anisotropies in the Electronic Charge Distribution in HNO2-Cis, DNO2-Cis, HNO2-Trans, and DNO2-Trans

1984 ◽  
Vol 39 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Dirk Hübner ◽  
Dieter H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Charge Distribution ◽  
Moment Tensor ◽  
Electronic Charge ◽  
Quadrupole Moments ◽  
Magnetic Susceptibility Anisotropy ◽  
Magnetic Susceptibility Tensor ◽  
Second Moments ◽  
Electronic Charge Distribution ◽  
Out Of Plane

The rotational Zeeman effect of the trans and eis forms of nitrous acid has been studied to yield the diagonal elements of the molecular g-tensor and the anisotropics in the diagonal elements of the magnetic susceptibility tensor. The results are used to calculate the diagonal elements of the molecular electric quadrupole moment tensor and the anisotropics in the second moments of the electronic charge distribution for all four molecular species. These data are compared to the corresponding CNDO/2 values, and the CNDO/2 value for the out of plane second moment of the electronic charge distribution is used together with the experimental anisotropics in the second moments of the electronic charge distribution to derive a semiexperimental value for the molecular bulk susceptibility which is otherwise difficult to obtain. The out-of-plane minus average in-plane magnetic susceptibility anisotropy is discussed with reference to the model of localised atomic susceptibilities and it is shown that the model should be extended to include bond and bond-bond interaction contributions.

scholarly journals The Rotational Zeeman Effect in Fluorobenzene and the Molecular Quadrupole Moment in Benzene

1982 ◽  
Vol 37 (10) ◽  
pp. 1165-1175 ◽  
Author(s):  
W. H. Stolze ◽  
M. Stolze ◽  
D. Hübner ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Carbon Tetrachloride ◽  
Quadrupole Moment ◽  
Ring Current ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Electric Quadrupole Moment ◽  
Microwave Spectrometer ◽  
Out Of Plane

The rotational Zeeman effect in fluorobenzene is reinvestigated with a resolution improved by a factor of almost five to give more accurate g-tensor elements, magnetic susceptibility anisotropics and molecular electric quadrupole moments. The results fit into the pictures of a linear dependence of the out of plane molecular electric quadrupole moment, Qcc, on the number of fluorine substituents and of a linear correlation between the nonlocal (ring current) susceptibility, Χccnonlocal, and the CNDO/2-π-electron density alternation. They lead to a gasphase molecular electric quadrupole moment in benzene, Qcc,benzene = - (28.4 ± 4.7) · 10-40 Cm2 which is slightly less negative than the value deduced from electric field-gradient birefringence experiments on dilute benzene solutions with carbon tetrachloride as solvent. A detailed description of the high resolution microwave spectrometer is given in the appendix.

The 14N Nuclear Quadrupole Coupling Tensors, the Tensors of the Molecular Magnetic Susceptibility and the Molecular Electric Quadrupole Moment in Pyrazole: A High Resolution Rotational Zeeman Effect Study

1990 ◽  
Vol 45 (11-12) ◽  
pp. 1248-1258 ◽  
Author(s):  
O. Böttcher ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
High Resolution ◽  
Quadrupole Moment ◽  
Moment Tensor ◽  
Electric Quadrupole ◽  
Coupling Constants ◽  
Zero Field ◽  
Electric Quadrupole Moment ◽  
Magnetic Susceptibility Anisotropy ◽  
Quadrupole Coupling

AbstractHigh resolution zero field and Zeeman rotational spectra of 1 D-pyrazole have been studied by microwave Fourier-transform spectroscopy. The zero field hfs patterns allowed to improve the quadrupole coupling constants for both 14N nuclei. From the high field Zeeman multiplets the diagonal elements of the g-tensor were obtained as gaa= -0.1178(2),.gbb=-0.0762(2) and gcc = 0.0608 (2). The two independent components of the molecular magnetic susceptibility anisotropy in units of 10-6 erg G-2 mole- 1 are 2 ξaa - ξbb - ξcc= 52.69(32) and 2 ξbb - ξcc - ξaa = 39.32(29) were, a, b, c denote the molecular principal inertia axes. From these values the components of the molecular electric quadrupole moment tensor in units of 10-26 esu cm2 follow as Qaa = 5.84(22), Qbb= -0.58 (21) and Qcc= -5.27(38). Comparison with corresponding values for the undeuterated species leads to the complete tensors including their orientation with respect to the nuclear frame.

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