Theory of Magnetic Properties of Molecules with Particular Emphasis on the Hydrogen Molecule

Hameka, Hendrik F.

doi:10.1103/revmodphys.34.87

Cited by 133 publications

(32 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[35] Calculation of NMR Parameters: The calculations of the NMR shielding constants were carried out at the all-electron MP2 level, using London orbitals. [49][50][51] The shielding constants were calculated with the Gaussian 98 program, [46] using the aug-cc-pCVTZ basis except for the Be atom, for which no core-valence functions are available and thus the aug-cc-pVTZ-su1 (see the description below) basis set was used instead. Quantum-mechanical calculations of the intermolecular spin-spin coupling constants have started only recently.…”

Section: Computational Sectionmentioning

confidence: 99%

The Properties of Weak and Strong Dihydrogen‐Bonded DH⋅⋅⋅HA Complexes

Cybulski¹,

Tymińska²,

Sadlej³

2006

ChemPhysChem

View full text Add to dashboard Cite

The properties of six dihydrogen-bonded (DHB) dimers with the BeH2 molecule as a proton acceptor were calculated by MP2, CCSD(T) and B3LYP methods. The structural, energetic and spectroscopic parameters are presented and analyzed in terms of their possible correlation with the interaction energy and the intermolecular H...H separation. The symmetry-adapted perturbation theory (SAPT) calculations were performed to gain more insight into the nature of the H...H interactions. The studied complexes are divided into three groups based on the calculated intermolecular distances and the interaction energies which range from approximately -1 to -42 kJ mol(-1). The analysis of the interaction energy components indicates that, in contrast to conventional hydrogen bonds, the induction energy is the most important term in the BeH2NH4+ complex. On the other hand, there is no sharp boundary between the DHB complexes classified as hydrogen bonded and van der Waals systems. The complexation-induced changes in vibrational frequencies and in proton shielding constants show a relationship with the interaction energy. The values of the 2hJXH and 3hJBeX coupling constants correlate well with the interaction energy and with the intermolecular distance.

show abstract

Section: Computational Sectionmentioning

confidence: 99%

The Properties of Weak and Strong Dihydrogen‐Bonded DH⋅⋅⋅HA Complexes

Cybulski¹,

Tymińska²,

Sadlej³

2006

ChemPhysChem

View full text Add to dashboard Cite

show abstract

“…The relationship between nuclear-spin rotation coupling constants and diamagnetic shielding of the nucleus has been discussed by Ramsey [1] and by Hameka [2]. It is clear that such a relationship should probably also be found for the case of the electron.…”

Section: Introductionmentioning

confidence: 94%

The relationship between electron spin rotation coupling constants andg-tensor components

Curl

1965

Molecular Physics

252

View full text Add to dashboard Cite

The Hamiltonian (Pauli approximation) which gives rise to the spinrotation coupling tensor and the electron spin g tensor is set up for a 2y~ polyatomic molecule. A relationship between the spin-rotation interaction and the Zeeman effect is suggested. The magnitudes of those terms which prevent this relationship from being exact are estimated. The relationship should be valid to two significant figures in the correction of the g factor from that of the free electron in most cases. Some comparisons with experiment are made.

show abstract

“…The saddle point optimizations give structures characterized by one imaginary frequency. The NMR chemical shifts were obtained from Gauge-Independent Atomic Orbital (GIAO) calculations [48][49][50] at the same level of theory, mPW1PW91/6-31+G(d,p), as the geometry optimization. To convert the chemical shifts to ppm and compare them with the experimental values, the calculated isotropic values were subtracted from the calculated isotropic values of 1 H and 13 C in optimized TMS (31.6515 and 196.597, respectively) at the same level of theory.…”

Section: Methodsmentioning

confidence: 99%

A theoretical investigation on the isomerism and the NMR properties of thiosemicarbazones

Silva

Albu

2007

Open Chemistry

View full text Add to dashboard Cite

Hybrid density functional theory calculations at the mPW1PW91/6-31+G(d,p) level of theory have been used to investigate the optimized structures and other molecular properties of five different series of thiosemicarbazones. The investigated compounds were obtained from acenaphthenequinone, isatin and its derivatives, and alloxan. The focus of the study is the isomerism and the NMR characterization of these thiosemicarbazones. It was found that only one isomer is expected for thiosemicarbazones and methylthiosemicarbazones, while for dimethylthiosemicarbazones, two isomers are possible. All investigated thiosemicarbazones exhibit a hydrazinic proton that is highly deshielded and resonates far downfield in the proton NMR spectra. This proton is a part of a characteristic sixmembered ring, and its NMR properties are a result of its strong, intermolecular hydrogen bond. The relationships between the calculated 1 H and 13 C NMR chemical shifts and various geometric parameters are reported.

show abstract

Theory of Magnetic Properties of Molecules with Particular Emphasis on the Hydrogen Molecule

Cited by 133 publications

References 25 publications

The Properties of Weak and Strong Dihydrogen‐Bonded DH⋅⋅⋅HA Complexes

The Properties of Weak and Strong Dihydrogen‐Bonded DH⋅⋅⋅HA Complexes

The relationship between electron spin rotation coupling constants andg-tensor components

A theoretical investigation on the isomerism and the NMR properties of thiosemicarbazones

Contact Info

Product

Resources

About