On a theoretical model for the Renner–Teller effect in tetra-atomic molecules

Perić, Miljenko; Ostojić, Bojana; Engels, Bernd

doi:10.1063/1.472641

Cited by 31 publications

(36 citation statements)

References 35 publications

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“…The model Hamiltonian we use is of the form [1], but now it involves two doubly degenerate bending modes. To represent them we chose the following four coordinates, introduced in our previous studies (18,19,22,23): (i) ρ T , the displacement (in radian) of the terminal nuclei from the B-B (≡z) axis at the trans-bending vibrations; (ii) φ T , the angle between the instantaneous molecular plane at the trans-bending vibrations and a space-fixed plane with the common z-axis; (iii) ρ C , the cisbending displacement coordinate; (iv) φ C , the angle between the molecular plane and the space-fixed plane at the cis-bending (see Fig. 1).…”

Section: Tetra-atomic Moleculesmentioning

confidence: 99%

“…The Hamiltonian also incorporates the electronic coordinate θ conjugate to the z-component of the electronic angular momentum operator, L z . Because of the use of the above defined symmetry coordinates the nuclear kinetic energy operator for small-amplitude bending vibrations represents the kinetic energy of two uncoupled twodimensional harmonic oscillators (18,19),…”

Section: Tetra-atomic Moleculesmentioning

confidence: 99%

“…However, as shown elsewhere (18,19), in the lowest-order approximation this quantity does not appear directly in the calculations but solely determines the selection rules for the matrix elements of the model Hamiltonian with respect to the nuclear basis functions. After integrating over all electronic coordinates except for θ , the electronic operator H e transforms into the "potential" for bending vibrations.…”

Section: Tetra-atomic Moleculesmentioning

confidence: 99%

“…Perturbative handling of the Renner-Teller effect in and electronic states of triatomic (15)(16)(17) and tetra-atomic (18)(19)(20) molecules has been the subject of considerable interest also in our laboratory. The main motivation for this work has been the attempt to build a bridge between the results of our ab initio studies and the corresponding experimental findings.…”

Section: Introductionmentioning

confidence: 99%

“…The present authors also prefer variational handling of problems such as the subject of the present study. Such an approach to the RennerTeller effect in tetra-atomic molecules has been developed in our laboratory (18,19,22,23). The range of its applicability has continuously been extended so that it enables us now to tackle also the spin-orbit and magnetic hyperfine effects (24)(25)(26), as well as large-amplitude bending vibrations (27,28).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Perturbative Handling of the Renner–Teller Effect and Spin–Orbit Coupling in Π Electronic States of Triatomic and Tetra-atomic Molecules

Perić

Peyerimhoff

2002

Journal of Molecular Spectroscopy

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Section: Tetra-atomic Moleculesmentioning

confidence: 99%

Section: Tetra-atomic Moleculesmentioning

confidence: 99%

Section: Tetra-atomic Moleculesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Perturbative Handling of the Renner–Teller Effect and Spin–Orbit Coupling in Π Electronic States of Triatomic and Tetra-atomic Molecules

Perić

Peyerimhoff

2002

Journal of Molecular Spectroscopy

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Mechanistic Study of the Reaction of Thiol‐Containing Enzymes with α,β‐Unsaturated Carbonyl Substrates by Computation and Chemoassays

Paasche¹,

Schiller²,

Schirmeister³

et al. 2010

ChemMedChem

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We investigated the reactions between substituted alpha,beta-unsaturated carbonyl compounds (Michael systems) and thiols by computations as well as chemoassays. The results give insight into variations in the underlying mechanisms as a function of the substitution pattern. This is of interest for the mechanisms of inhibition of the SARS coronavirus main protease (SARS-CoV M(pro)) by etacrynic acid derivatives as well as for the excess toxicity of substituted alpha,beta-unsaturated carbonyl compounds. This study compares possible reaction courses including 1,4-addition followed by a ketonization step, and underscores the importance of a base-catalyzed step for the reactivity of thiol groups in enzymes. Phenyl and methyl substituents at the Michael system decrease the reactivity of the electrophilic compound, but chlorophenyl substituents partly recover the reactivity. Computations also indicate that electron-pushing substituents lead to a change in the reaction mechanism. The conformation of the Michael system is also found to significantly influence reactivity: the s-cis conformation leads to higher reactivity than the s-trans conformation. The computed data explain the trends in measured inhibition potencies of substituted alpha,beta-unsaturated carbonyl compounds and of reaction rates in chemical assays. They also indicate that the reversibility of inhibition does not stand in contrast to the formation of a new covalent bond between inhibitor and protease.

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Use of the normal coordinates in variational and perturbative ab initio handling of the vibronic and spin–orbit couplings in Π electronic states of linear tetra‐atomic molecules

Perić

Stevanović

2003

Int J of Quantum Chemistry

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ABSTRACT:A variational and a perturbative approach are developed to handle the combined effect of the vibronic and spin-orbit couplings in ⌸ electronic states of tetraatomic molecules with linear equilibrium geometry. Both of them are based on the use of the normal vibrational bending coordinates. The perturbative treatment is carried out via two schemes for partition of the model Hamiltonian: In the first, the spin-orbit coupling term is treated as a perturbation; in the second, it is included in the zerothorder Hamiltonian. It is demonstrated that both perturbative approaches lead to the same second-order formulae when the spin-orbit coupling constant is small compared to the bending frequency, but much larger than the splitting of potential surfaces upon bending. These approaches are used to calculate the vibronic and spin-orbit structure in the X 2 ⌸ electronic state of HCCS by employing the ab initio-computed potential energy surfaces. Complete numerical equivalence of the results obtained with the present variational approach and those generated by the algorithms employing internal vibrational coordinates is demonstrated. The restrictions concerning the applicability of the perturbative approaches are discussed in terms of the agreement between the results obtained by means of them with those generated in the corresponding variational computations. The general reliability of the model employed is checked by comparing the theoretical results with the available experimental data.

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On a theoretical model for the Renner–Teller effect in tetra-atomic molecules

Cited by 31 publications

References 35 publications

Perturbative Handling of the Renner–Teller Effect and Spin–Orbit Coupling in Π Electronic States of Triatomic and Tetra-atomic Molecules

Perturbative Handling of the Renner–Teller Effect and Spin–Orbit Coupling in Π Electronic States of Triatomic and Tetra-atomic Molecules

Mechanistic Study of the Reaction of Thiol‐Containing Enzymes with α,β‐Unsaturated Carbonyl Substrates by Computation and Chemoassays

Use of the normal coordinates in variational and perturbative ab initio handling of the vibronic and spin–orbit couplings in Π electronic states of linear tetra‐atomic molecules

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