Ab initio calculations of stretching vibrational transitions for the linear molecules HCN, HNC, HCCF and HC3N up to high overtones

Botschwina, Peter; Schulz, Bernd; Horn, Matthias; Matuschewski, M.

doi:10.1016/0301-0104(94)00350-j

Cited by 74 publications

(27 citation statements)

References 34 publications

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“…The anharmonic FCF method proposed in this investigation is mainly based on that of Botschwina et al 22 One main reason for choosing this approach is that it can be readily incorporated into our existing harmonic FCF model ͑see the later text͒. In this way, the Duschinsky effect, which is not considered in the method of Botschwina et al, as mentioned previously, can be included in the present anharmonic FCF method.…”

Section: A Anharmonic Fcf Methodsmentioning

confidence: 99%

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A new method of calculation of Franck–Condon factors which includes allowance for anharmonicity and the Duschinsky effect: Simulation of the He I photoelectron spectrum of ClO2

Mok

Lee

Chau

et al. 2000

The Journal of Chemical Physics

106

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A new method of Franck-Condon ͑FC͒ factor calculation for nonlinear polyatomics, which includes anharmonicity and Duschinsky rotation, is reported. Watson's Hamiltonian is employed in this method with multidimensional ab initio potential energy functions. The anharmonic vibrational wave functions are expressed as linear combinations of the products of harmonic oscillator functions. The Duschinsky effect, which arises from the rotation of the normal modes of the two electronic states involved in the electronic transition, is formulated in Cartesian coordinates, as was done previously in an earlier harmonic FC model. This new anharmonic FC method was applied to the simulation of the bands in the He I photoelectron ͑PE͒ spectrum of ClO 2 . For the first band, the harmonic FC model was shown to be inadequate but the anharmonic FC simulation gave a much-improved agreement with the observed spectrum. The experimentally derived geometry of the X 1 A 1 state of ClO 2 ϩ was obtained, for the first time, via the iterative FC analysis procedure ͕R(Cl-O͒ϭ1.414Ϯ0.002 Å, ЄO-Cl-Oϭ121.8Ϯ0.1°͖. The heavily overlapped second PE band of ClO 2 , corresponding to ionization to five cationic states, was simulated using the anharmonic FC code. The main vibrational features observed in the experimental spectrum were adequately accounted for in the simulated spectrum. The spectral simulation reported here supports one of the two sets of published assignments for this band, which was based on multireference configuration interaction ͑MRCI͒ calculations. In addition, with the aid of the simulated envelopes, a set of adiabatic ͑and vertical͒ ionization energies to all five cationic states involved in this PE band, more reliable than previously reported, has been derived. This led also to a reanalysis of the photoabsorption spectrum of ClO 2 .

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Section: A Anharmonic Fcf Methodsmentioning

confidence: 99%

“…Botschwina and co-workers are one of the few research groups performing anharmonic FCF calculations in this way. 22,23 Recently, details of a few other types of anharmonic FCF methods have been published. [24][25][26][27][28] The major application of FCF calculations is in spectral simulation.…”

Section: Introductionmentioning

confidence: 99%

A new method of calculation of Franck–Condon factors which includes allowance for anharmonicity and the Duschinsky effect: Simulation of the He I photoelectron spectrum of ClO2

Mok

Lee

Chau

et al. 2000

The Journal of Chemical Physics

106

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“…Typical example is cyanopolyacetylenes HC 2n+1 N. HC 11 N 8 is one of the largest molecules observed in interstellar medium. The structures and infrared frequencies of these molecules were measured, and numerous ab initio computations [9][10][11][12] were also carried out.…”

Section: Introductionmentioning

confidence: 99%

Structure, Spectroscopic Properties and Reactions of Interstellar Molecule HC₂N and Isomers :Ab initio Study

2002

Bulletin of the Korean Chemical Society

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Calculations are presented for the molecule HC 2 N and its geometrical isomers. The structures, harmonic frequencies and dipole moments are reported. The potential energy surface of the [H,C,C,N] system is investigated in detail, and the transition states, intermediate complexes, and the energies of barrier for the isomerization and dissociation reactions are computed in order to determine the reaction paths and to estimate the stability of the isomers. The barriers of isomerization among HCCN, HCNC and HNCC are computed to be rather large and dissociations of these molecules are highly endothermic, indicating that these molecules are kinetically stable. The association reactions HC + CN → HCCN, HC + NC → HCNC, and HN + CC → HNCC are barrierless and very exothermic, suggesting that they may be considered as efficient means of producing the HCCN and the isomers in the laboratory and in interstellar space.

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“…In this way, the anharmonic vibrational FCF can be reduced to a sum of harmonic overlap integrals, which can be evaluated readily with available analytical formulas. Botschwina and coworkers are one of the few research groups performing anharmonic FCF calculations in this way [39]. Recently, details of a few other types of anharmonic FCF methods have been published [3,6,40 -42].…”

Section: Resultsmentioning

confidence: 99%

Geometries of the Halocarbene anions HCF− and CF2−: ab initio calculation and Franck–Condon analysis

Liang

Kong

Zhang

et al. 2004

Journal of Molecular Structure: THEOCHEM

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Ab initio calculations of stretching vibrational transitions for the linear molecules HCN, HNC, HCCF and HC3N up to high overtones

Cited by 74 publications

References 34 publications

A new method of calculation of Franck–Condon factors which includes allowance for anharmonicity and the Duschinsky effect: Simulation of the He I photoelectron spectrum of ClO2

A new method of calculation of Franck–Condon factors which includes allowance for anharmonicity and the Duschinsky effect: Simulation of the He I photoelectron spectrum of ClO2

Structure, Spectroscopic Properties and Reactions of Interstellar Molecule HC₂N and Isomers :Ab initio Study

Geometries of the Halocarbene anions HCF− and CF2−: ab initio calculation and Franck–Condon analysis

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Ab initio calculations of stretching vibrational transitions for the linear molecules HCN, HNC, HCCF and HC3N up to high overtones

Cited by 74 publications

References 34 publications

A new method of calculation of Franck–Condon factors which includes allowance for anharmonicity and the Duschinsky effect: Simulation of the He I photoelectron spectrum of ClO2

A new method of calculation of Franck–Condon factors which includes allowance for anharmonicity and the Duschinsky effect: Simulation of the He I photoelectron spectrum of ClO2

Structure, Spectroscopic Properties and Reactions of Interstellar Molecule HC2N and Isomers :Ab initio Study

Geometries of the Halocarbene anions HCF− and CF2−: ab initio calculation and Franck–Condon analysis

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Structure, Spectroscopic Properties and Reactions of Interstellar Molecule HC₂N and Isomers :Ab initio Study