Analysis of the Quadrupole Coupling Constants and Mössbauer Iso- meric Shifts in Halogen Compounds Within the Gaussian98 Code

A comparison of the experimental and calculated nuclear quadrupole coupling constants of diatomic halogen, interhalogen, trihalide ions and complexes of pyridine is a good test of reliability of semiempirical and non-empirical theories as well as their usefulness in the interpretation of quadrupole coupling data from the qualitative and quantitative point of view. Therefore, a practical way of gaining insight into the bonding properties and electronic structure of such systems consists of combining semiempirical MO calculations with experimental data to derive reliable information. In the present work we report the results of ab initio studies of several iodine containing molecules and ions using the calculated NQCC as a test of the quality of the wavefunctions. To demonstrate the quality of our calculations, we compare the calculated halogen-halogen bond length and QCC with the corresponding experimental values for the compounds studied. With a few exceptions, the overall agreement with experiment is most satisfactory. The results on dipole moments and energy levels are also in a good agreement with the experimental data, however these quantities were measured only in the few cases.

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The Rovibrational Dependence of the 14N Nuclear Quadrupole Coupling Constants in the X2Σ+ and B2Σ+ States of CN from the Multireference CI Approach

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20030509 ◽

2003 ◽

Vol 68 (3) ◽

pp. 509-528 ◽

Cited By ~ 6

Author(s):

Rudolf Polák ◽

Jiří Fišer

Keyword(s):

Dipole Moments ◽

Wave Functions ◽

Coupling Constants ◽

Basis Sets ◽

Configuration Spaces ◽

Spectroscopic Constants ◽

Quadrupole Coupling ◽

Correlation Consistent ◽

Consistent Basis

In using several augmented correlation-consistent basis sets and reference configuration spaces, the 14N quadrupole coupling constants (QCCs) of rovibrational levels of the X2Σ+ and B2Σ+ states of the CN radical are computed from internally contracted multireference configuration interaction wave functions. To examine the overall quality of the correlated wave functions used for computing the expectation values of the electric field gradient (EFG) tensor at the N nucleus, electric dipole moments are calculated and spectroscopic constants are derived from corresponding potential energy curves. The adequacy of the expectation value approach to the evaluation of the EFG and dipole moment is discussed. The calculated vibrational dependence of the 14N QCC compares reasonably with the available experimental data.

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Density Functional Theory Studies of Bonding in Complexes H3N···XY of Ammonia and Dihalogen Molecules: A Comparison with Experimental Results from Rotational Spectroscopy

Zeitschrift für Naturforschung A ◽

10.1515/zna-2002-6-746 ◽

2002 ◽

Vol 57 (6-7) ◽

pp. 537-543 ◽

Cited By ~ 9

Author(s):

O. Kh. Poleshchuk ◽

A. C. Legona

Keyword(s):

Density Functional ◽

Natural Bond Orbital ◽

Coupling Constants ◽

Rotational Spectroscopy ◽

Charge Redistribution ◽

Functional Theory ◽

Quadrupole Coupling ◽

Nuclear Quadrupole ◽

Experimental Values

The electron density and nuclear quadrupole coupling constants (NQCC) of the H3N...XY (n a type in Mulliken notation) complexes, (X, Y = F, Cl, Br and I), are analyzed with the aid of density functional calculations. To demonstrate the quality of the calculations, various bond lengths and NQCCs obtained by using the hybrid Becke-Lee-Perdew-Yang functional are compared with the corresponding experimental values determined from rotational spectroscopy. An analysis of the NQCC values and various quantities derived fromthe natural bond orbital approach reveals that the molecular interaction is mainly electrostatic, with probably only a small extent of intermolecular electric charge redistribution on complex formation

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Microwave Spectrum, Quadrupole Coupling Constants, and Dipole Moments of 1-Chloro-2-fluorobenzene

Journal of Molecular Spectroscopy ◽

10.1006/jmsp.1996.0056 ◽

1996 ◽

Vol 176 (1) ◽

pp. 17-22 ◽

Cited By ~ 8

Author(s):

Masao Onda ◽

Tsuaki Odaka ◽

Hideya Miyazaki ◽

Masayoshi Mori ◽

Ichiro Yamaguchi ◽

...

Keyword(s):

Dipole Moments ◽

Microwave Spectrum ◽

Coupling Constants ◽

Quadrupole Coupling

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Aspects of hybridization

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1950.0119 ◽

1950 ◽

Vol 202 (1071) ◽

pp. 548-564 ◽

Cited By ~ 41

Keyword(s):

Dipole Moments ◽

Atomic Orbital ◽

Second Order ◽

Coupling Constants ◽

Covalent Bonds ◽

Orbital Hybridization ◽

Quadrupole Coupling ◽

Orbital Approximation ◽

Nuclear Quadrupole ◽

Oxygen Atoms

It has been shown that the pairing theory of orbital hybridization accounts satisfactorily for the variations which are observed in the properties of C-H bonds. Since heteropolar effects are in the opposite directions to the effects described, it is concluded that hybridization influences the properties of predominantly covalent bonds to a greater extent than do differences in electronegativity. The extent of second-order hybridization in the molecules CH, NH and OH has been dealt with in the light of this analysis. The consequences of the electronegativity concept have been examined on the basis of a generalized atomic orbital approximation. In particular, variations of the electronegativity of the carbon, nitrogen and oxygen atoms in different states of hybridization have been analyzed. The idea of 'lone' electrons has been formalized and the results of this definition have been discussed. Finally, the effects of orbital hybridization on the dipole moments and nuclear quadrupole coupling constants of molecules have been considered.

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Microwave Spectrum, Conformation Equilibrium, Intramolecular Hydrogen Bonding, Dipole Moments, 14N Nuclear Quadrupole Coupling Constants and Centrifugal Distortion Constants of 2-Fluoroethylamine.

Acta Chemica Scandinavica ◽

10.3891/acta.chem.scand.34a-0015 ◽

1980 ◽

Vol 34a ◽

pp. 15-29 ◽

Cited By ~ 23

Author(s):

K.-M. Marstokk ◽

Harald Møllendal ◽

Denis A. Kohl ◽

Dinko Tuhtar ◽

Johan Sjöblom ◽

...

Keyword(s):

Hydrogen Bonding ◽

Dipole Moments ◽

Intramolecular Hydrogen Bonding ◽

Microwave Spectrum ◽

Coupling Constants ◽

Centrifugal Distortion ◽

Quadrupole Coupling ◽

Nuclear Quadrupole ◽

Centrifugal Distortion Constants ◽

Intramolecular Hydrogen

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The ab initio Calculation of Nuclear Quadrupole Coupling Constants with Special Reference to 33S

Zeitschrift für Naturforschung A ◽

10.1515/zna-1992-1-235 ◽

1992 ◽

Vol 47 (1-2) ◽

pp. 203-216 ◽

Cited By ~ 3

Author(s):

Michael H. Palmer

Keyword(s):

Experimental Data ◽

Ab Initio ◽

Ab Initio Calculation ◽

Coupling Constants ◽

Basis Set ◽

Equilibrium Geometry ◽

Relaxation Methods ◽

Quadrupole Coupling ◽

Nuclear Quadrupole ◽

The Relationship

AbstractThe ab initio calculation of 33S nuclear quadrupole coupling constants (NQCC) for a range of S-containing compounds with S2, S4 and S6 bonding types is described. All of the calculations used a triple zeta valence + polarisation basis set (TZVP) of gaussian type orbitals; all of the molecules were studied at the TZVP equilibrium geometry. The electric field gradients (EFG) calculated were correlated with the experimental NQCC obtained by either microwave spectroscopy (MW), nuclear quadrupole resonance (NQR) or NMR relaxation methods; although the experimental data cover a wide diversity of chemical types over a long period of time, the slope of the relationship between the EFG (qii) and the NQCC (χii) yields a value for the 33S atomic quadrupole moment of - 0.064 barn, very close to recent calculations with a large atomic basis set, and to experimental data. The relationship between the EFG tensor components and the internal molecular structure features is discussed for a diverse series of molecules.

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The Charge Distribution in Amides and Thioamides by Nuclear Quadrupole Coupling, Dipole Moments and Electronic Structure Calculations

Zeitschrift für Naturforschung A ◽

10.1515/zna-1996-5-622 ◽

1996 ◽

Vol 51 (5-6) ◽

pp. 460-478

Author(s):

Michael H. Palmer ◽

Paul Sherwood

Keyword(s):

Dipole Moments ◽

Lone Pair ◽

Coupling Constants ◽

Hartree Fock ◽

Quadrupole Coupling ◽

Quadrupole Resonance ◽

Electron Contribution ◽

Nuclear Quadrupole ◽

Moller Plesset ◽

Structure Calculations

AbstractThe nuclear quadrupole coupling constants from microwave spectroscopy (MW) and quadrupole resonance (NQR) for amides and thioamides are discussed in relation to Hartree-Fock calculations with and without Moller-Plesset correlation effects. The view that the larger dipole moments from thioamides than the corresponding amides is a function of enhanced resonance in the former is discussed and (in effect) confirmed by the present procedures. The principal mechamism seems to be the push/pull π/σ effects of the N atom with respect to the CO and CS groups, with S being a better σ-donor than O; however, the effect is still present with formamidine where no electronegativity effects are important, so the overall effect is the 2,1,1 π-electron contribution to the allylic system from N, C, O(S). The use of localised MO’s and NO’s is described, and the centroid positions are discussed in relation to the polarity of the bonds. The LMO’s largely truncate the contributions to each NQCC to the three attached bonds (or 2 bonds + a lone pair orbital at O or S), as is used in the Townes-Dailey procedures. More distant LMO’s generally contribute < 0.05 a. u. to the EFG, simplifying the analysis. The effects of O( or S)-protonation of urea and thiourea is discussed.

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Microwave Absorption Spectra of AlF, GaF, InF, and TIF

Zeitschrift für Naturforschung A ◽

10.1515/zna-1970-0706 ◽

1970 ◽

Vol 25 (7) ◽

pp. 1029-1035 ◽

Cited By ~ 43

Author(s):

J. Hoeft ◽

F. J. Lovas ◽

E. Tiemann ◽

T. Törring

Keyword(s):

Vibrational State ◽

Stark Effect ◽

Dipole Moments ◽

Electric Quadrupole ◽

Spin Rotation ◽

Coupling Constants ◽

Coupling Constant ◽

Vibrational States ◽

Electric Dipole Moments ◽

Quadrupole Coupling

Observation of various rotational transitions of four Group Ilia monofluoride allowed the Dunham coefficients Y01, Y11, Y21 and Y12 to be determined. From the hyperfine structure of the AlF, GaF and InF spectra, the nuclear electric quadrupole coupling constants, e qv Q, and spin-rotation coupling constant, CI, were obtained for several vibrational states, v: e qv Q(27 Al19F) = -37,75(8) + 0,44(8) (v + 1/2) MHz,e qv Q(69 Ga19F) = -107,07(8) + 1,09(7) (v + 1/2) MHz,e qv Q(71 Ga19F) = -67,46(8) + 0,68(7) (v + 1/2) MHz,e qv Q(115 In19F) = -727,06(20) + 6,64(20) (v + 1/2) MHz.Stark effect measurements on GaF and InF in the ground vibrational state resulted in the following electric dipole moments:69Ga 19F: |μ̄| = 2,45 (5) D,115In 19F: |μ̄| = 3,40 (7) D

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Cooperativity between the hydrogen bonding and σ-hole interaction in linear NCX···(NCH)n=2–5 and O3Z···(NCH)n=2–5 complexes (X = Cl, Br; Z = Ar, Kr): a comparative study

Canadian Journal of Chemistry ◽

10.1139/cjc-2016-0640 ◽

2017 ◽

Vol 95 (5) ◽

pp. 537-546 ◽

Cited By ~ 4

Author(s):

Mehdi D. Esrafili ◽

Hossein Kiani

Keyword(s):

Hydrogen Bonding ◽

Coupling Constants ◽

Interaction Energies ◽

Cooperative Effects ◽

Orbital Interactions ◽

Quadrupole Coupling ◽

Bonding Properties ◽

Cooperativity Effects ◽

Nuclear Quadrupole ◽

Substantial Change

Quantum chemical calculations are performed to investigate the cooperativity of hydrogen bonding with halogen or aerogen bonding interactions in linear NCX···(NCH)n=2–5 and O3Z···(NCH)n=2–5 clusters, where X = Cl, Br and Z = Ar, Kr. To understand the cooperativity mechanism in these systems, the corresponding binary NCX···NCH and O3Z···NCH complexes are also considered. The binding distances, interaction energies, and bonding properties of the NCX···(NCH)n=2–5 and O3Z···(NCH)n=2–5 clusters are analyzed in detail. It is found that the cooperative effects in the hydrogen bonding tend to strengthen X···N and Z···N interactions. For both NCX···(NCH)n and O3Z···(NCH)n clusters, a small bond shrinkage is observed from n = 4 to n = 5, which suggests that the cooperativity effects are almost saturated in the larger clusters (n > 5). As the size of the X or Z atom is increased, the magnitude of the cooperative energy in these systems is also increased, which is mainly ascribed to changes in electrostatic potentials and orbital interactions. Our results indicate that the cooperative effects lead to a substantial change in the 14N nuclear quadrupole coupling constants of the NCH molecule.

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