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 of Imines II. Cis- and Trans-Ethanimine and Trans-Syn- and Trans-Anti-Propenimine, their g-Tensors, Magnetic Susceptibility Anisotropics, Molecular Electric Quadrupole Moments, 14N Nuclear Quadrupole Coupling Constants, and 14N Spin-Rotation Coupling Constants; a Microwave Spectroscopic Study Combined with Quantum Chemical Calculations

1991 ◽  
Vol 46 (9) ◽  
pp. 785-798 ◽  
Author(s):  
H. Krause ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
High Field ◽  
Moment Tensor ◽  
Electric Quadrupole ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Zero Field ◽  
Quadrupole Moments ◽  
Quadrupole Coupling ◽  
Nuclear Quadrupole

Abstract The zero field 14N-hfs-multiplets and the high-field Zeeman-hfs-multiplets of low-J rotational transitions of the title compounds were observed in a flash pyrolysis setup under high-resolution conditions. From the zero-field hfs patterns the 14N spin-rotation coupling constants and the 14N nuclear quadrupole coupling constants were obtained. From the high-field Zeeman-hfs-multiplets, the diagonal elements of the molecular g-tensor and the anisotropies in the diagonal elements of the molecular magnetic susceptibility tensor were determined and were used to derive the diagonal elements of the molecular electric quadrupole moment tensor. INDO calculations and restricted Hartree-Fock self consistent field calculations with a basis of TZVP quality were carried out at the experimental structures and critically compared to the experimental results

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.

The Rotational Zeeman Effect of 1,2,4-Trifluorobenzene

1989 ◽  
Vol 44 (7) ◽  
pp. 687-691 ◽  
Author(s):  
W. H. Stolze ◽  
D. H. Sutter
Keyword(s):  
Ground State ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Expectation Values ◽  
Magnetic Susceptibility Tensor ◽  
Second Moments ◽  
Plane Component ◽  
Out Of Plane ◽  
State Expectation

Abstract The rotational Zeeman effect of 1,2,4-trifluorobenzene has been studied for 8 low-J rotational transitions in magnetic fields between 1.9 and 2.4 Tesla. The observed susceptibility anisotropics and molecular g-values are: (2χaa−χbb−χcc) = 37.85(69) • 10−6 erg G−2 mole−1, (2χbb−χcc−χaa) = 56.85(54) • 10−6 erg G−2 mole−1, gaa= −0.0393(3), gbb= −0.0277(3), and gcc = 0.0042(2). The Zeeman parameters have been used to derive the molecular electric quadrupole moments and vibronic ground state expectation values for the electronic second moments. The observed out-of-plane quadrupole moment is discussed with reference to an additivity scheme proposed earlier. The observed out-of-plane component of the molecular magnetic susceptibility tensor is in excellent agreement with the value predicted earlier from the CNDO/2-π-electron density alternation at the ring atoms.

scholarly journals Molecular ɡ-values, Magnetic Susceptibility Anisotropics, Molecular Electric Quadrupole Moments, improved Molecular Electric Dipole Moments and 14N-Quadrupole Coupling Constants of Acrylonitrile, H2C = CH—CN, and the Magnetic Susceptibility Tensor of the Nitrile Group

1985 ◽  
Vol 40 (10) ◽  
pp. 998-1010
Author(s):  
M. Stolze ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Dipole Moments ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Nitrile Group ◽  
Coupling Constants ◽  
Electric Dipole Moments ◽  
Susceptibility Tensor ◽  
Magnetic Susceptibility Tensor ◽  
Quadrupole Coupling

The highfield, linear and quadratic Zeeman effect has been observed in Acrylonitrile (Vinyl Cyanide). The Zeeman multiplets are complicated by the presence of the 14N nuclear quadrupole coupling, however the 14N nuclear Zeeman effect effectively uncouples 14N spin from the rotational angular momentum. This uncoupling was used to derive improved molecular electric dipole moments from the Stark-shifts in the 211 ← 202 and 312 ← 303 rotational transitions observed under ΔMj=0 selection rule in the presence of a high magnetic field. They are |μa| = 3.815(12)D and |μb| = 0.894(68)D, respectively. From the zero field hfs multiplets, observed under high resolution conditions, improved 14N quadrupole coupling constants were obtained: χaaN = - 3.7800(21) MHZ, χbbN - χccN = - 0.4200(89) MHz. They are discussed with reference to the structure of the Nitrile group. From the Zeeman splittings of the 101 ← 000, 110 ← 101, 211 ← 202 and 312 ← 303 rotational transitions observed under ΔMj = 0 and ΔMj = ± 1 selection rule, the diagonal elements of the molecular g-tensor and the anisotropics in the diagonal elements of the molecular magnetic susceptibility tensor were obtained as gaa = -0.17901(33), gbb, = - 0.04585(17), gcc = -0.01820(16) and 2 χaa - χbb - χcc = - 7.22(25) 10-6 erg G-2 mole-1 and 2χbb - χcc - χaa = + 15.90(31) 10-6 erg G-2 mole-1.They are discussed with reference to the molecular electric quadrupole moment, the paramagnetic and diamagnetic contributions to the molecular susceptibilities, and the second moments of the electronic charge distribution. The susceptibility data are also used to derive the magnetic susceptibility tensor contribution of the Nitrile group.

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

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.

Molecular g-Values, Magnetic Susceptibility Anisotropics, Second Moments of the Charge Distribution, and Molecular Electric Quadrupole Moments in trans- and cis-Thioformic Acid

1978 ◽  
Vol 33 (1) ◽  
pp. 29-37 ◽  
Author(s):  
G. K. Pandey ◽  
D. H. Sutter
Keyword(s):  
Magnetic Susceptibility ◽  
Charge Distribution ◽  
Zeeman Effect ◽  
Electric Quadrupole ◽  
Covalent Bonding ◽  
Microwave Spectrum ◽  
Quadrupole Moments ◽  
Second Moments ◽  
In Trans ◽  
Single Standard

The rotational Zeeman effect in the microwave spectrum of trans- and cis-Thioformic Acid has been investigated at field strengths upto 25.6 kG. Measurements were done for both ⊿M = 0 and ⊿M = ± 1 selection rules for the trans species and for ⊿M = ±1 for the cis species. From the observed splittings the following parameters were obtained for the diagonal elements of the molecular g tensor and the susceptibility anisotropics.(all experimental uncertinties are single standard deviations).The molecular electric quadrupole moments derived from the Zeeman data indicate that there is no significant covalent bonding in the O…H region of the trans species.

High Resolution Study of the Rotational Spectrum of Formaldoxime, Combined with Quantum Chemical Calculations, Its 14N Spin-Rotation Coupling, 14N Nuclear Quadrupole hfs, and Its Rotational Zeeman-Effect

1990 ◽  
Vol 45 (6) ◽  
pp. 817-826 ◽  
Author(s):  
A. Klesing ◽  
D. H. Sutter
Keyword(s):  
High Resolution ◽  
Quadrupole Moment ◽  
Moment Tensor ◽  
Electric Quadrupole ◽  
Spin Rotation ◽  
Coupling Constants ◽  
Zero Field ◽  
Rotational Spectrum ◽  
Electric Quadrupole Moment ◽  
Resolution Study

AbstractA high resolution study of the rotational spectrum of formaldoxime was carried out with the aim to resolve a discrepancy between early microwave results and recent ab initio calculations. Accurate 14N quadrupole coupling constants and spin-rotation coupling constants could be derived from zero field hfs multiplets. From the Zeeman-splittings in external magnetic fields up to 18kGauss the diagonal elements of the molecular g-tensor and the anisotropics in the diagonal elements of the molecular magnetic susceptibility tensor were obtained and were used to derive the diagonal elements of the molecular electric quadrupole moment tensor. For comparison, Hartree Fock SCF calculations were carried out with a basis of TZVP quality. As it turned out such calculations are able to reproduce the molecular electric quadrupole moment tensor but fail to reproduce the 14N nuclear qudrupole coupling constants to better than 0.3 MHz. A revised formula to predict spinrotation coupling constants of first row elements such as nitrogen is also proposed.

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