A theoretical study of the absorption spectrum of singlet CH 2

Gu, Jie; Hirsch, Gerhard; Buenker, Robert J.; Brumm, Martin; Osmann, Gerald; Bunker, P. R.; Jensen, Per

doi:10.1016/s0022-2860(99)00256-2

Cited by 50 publications

(109 citation statements)

References 42 publications

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“…Therefore several experimental T e energies are shown in Table 6. Most reliable experimental energies are (9.215 ± 0.004) kcal/mol [9] and (9.032 ± 0.057) kcal/mol [47] which fit the range of the calculated CCSD(T) ∆CBS limit energies between 9.04 and 9.48 kcal/mol.…”

Section: Singlet-triplet Energy Gapsupporting

confidence: 65%

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Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet Methylene in Four consecutive Dunning Basis Sets with Extrapolations to Infinite Limits for Various Molecular Properties

Neugebauer

Häfelinger

2005

IJMS

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: Stationary points for four geometrically different states of methylene: bent and linear triplet methylene, bent and linear singlet methylene were investigated using the highly reliable post-HF CCSD(T) method. Extrapolations to the CCSD(T) basis set (CBS) limit from Dunning triple to quintuple correlation consistent polarized basis sets were performed for total energies, for the equilibrium CH distances r e (CH), for singlettriplet separation energies, for energy barriers to linearity and for correlation energies. Post-HF calculations with Dunning basis sets of the literature are presented for comparisons.Keywords: Ab initio CCSD(T) calculations; Extrapolations to Dunning basis set limits of infinity; Geometry of stationary points for lowest triplet and singlet states of methylene; Total energies, singlet-triplet separation energies, barriers to linearity and correlation energies Int. J. Mol. Sci. 2005, 6 158

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Section: Singlet-triplet Energy Gapsupporting

confidence: 65%

“…In Table 6 we show the basis set and method dependence of calculated T e values derived as difference between the total energies of the minima 3 and 1 presented in Tables 2 and 1 and some additional references [45], [46] and [47].…”

Section: Singlet-triplet Energy Gapmentioning

confidence: 99%

Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet Methylene in Four consecutive Dunning Basis Sets with Extrapolations to Infinite Limits for Various Molecular Properties

Neugebauer

Häfelinger

2005

IJMS

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“…We can easily achieve this since, at each nuclear geometry, we are free to change the signs of one or more of the three electronic wavefunctions, thus changing the signs of the electronic integrals in Eqs. [1]- [3]. With our phase convention for the two electronic functions ψ (8) is satisfied), we found in Ref.…”

Section: Figmentioning

confidence: 67%

“…Theoretical interest arises because thẽ a andb states of CH 2 correlate with a 1 g state at linearity and are therefore involved in a Renner-Teller interaction; the most recent theoretical study of this system is in (3). In (1) Herzberg and Johns also reported the observation of a fragment of a near ultraviolet electronic band system which they were unable to analyze.…”

Section: Introductionmentioning

confidence: 99%

“…The aim of the present paper is to reconcile our simulation of thec B 1 ) band system with this observed spectrum. In order to simulate the spectrum we have calculated ab initio thec-ã andc-b transition moment surfaces, and used the MORBID (4-7 ) and RENNER (8)(9)(10) program systems with previously determined potential energy surfaces for theã (3),b (3), andc (11) states in a calculation of the energy levels and wavefunctions.…”

Section: Introductionmentioning

confidence: 99%

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The Near Ultraviolet Band System of Singlet Methylene

Yurchenko

Jensen

et al. 2001

Journal of Molecular Spectroscopy

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Comprehensive Quantum Chemical Characterization of the Astrochemically Relevant HC_nH Chain Family: An Attempt to Aid Astronomical Observations

Bâldea

2022

Advcd Theory and Sims

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In this paper, the results of a comprehensive theoretical investigation of neutral HC n H 0 and charged HC n H ± chains are reported using state-of-the-art compound model chemistries (W1BD, G4, CBS-QB3, CBS-APNO, CBS-4M) and single point methods (including "gold standard" CCSD(T)). The properties envisaged include electronic and chemical bonding structure data, enthalpies of formation, adiabatic and vertical ionization (IP), and electron attachment (EA) energies, gas phase acidities, C−H bond strengths, and chain "deprotecting" (HC n H → H + C n + H) energies. The best theoretical estimates based on composite models reported here for the various properties investigated agree with the available experimental data and are better than all previous theoretical estimates. To exemplify, for the enthalpies of formation, the G4 composite model achieves a RSMD (root square mean deviation) of 0.28 kcal mol −1 and a MUD (maximum unsigned deviation) of 0.45 kcal mol −1 . Most importantly from the astrochemical perspective, it is predicted that the stable HC n H − anions with n ≤ 8 are nonlinear. Having sufficiently large dipole moments, the anion HC n H − cis conformers are potential candidates for detection in space via rovibrational spectroscopy.

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A theoretical study of the absorption spectrum of singlet CH 2

Cited by 50 publications

References 42 publications

Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet Methylene in Four consecutive Dunning Basis Sets with Extrapolations to Infinite Limits for Various Molecular Properties

Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet Methylene in Four consecutive Dunning Basis Sets with Extrapolations to Infinite Limits for Various Molecular Properties

The Near Ultraviolet Band System of Singlet Methylene

Comprehensive Quantum Chemical Characterization of the Astrochemically Relevant HC_nH Chain Family: An Attempt to Aid Astronomical Observations

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A theoretical study of the absorption spectrum of singlet CH 2

Cited by 50 publications

References 42 publications

Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet Methylene in Four consecutive Dunning Basis Sets with Extrapolations to Infinite Limits for Various Molecular Properties

Ab initio post-HF CCSD(T) Calculations for Triplet and Singlet Methylene in Four consecutive Dunning Basis Sets with Extrapolations to Infinite Limits for Various Molecular Properties

The Near Ultraviolet Band System of Singlet Methylene

Comprehensive Quantum Chemical Characterization of the Astrochemically Relevant HCnH Chain Family: An Attempt to Aid Astronomical Observations

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Comprehensive Quantum Chemical Characterization of the Astrochemically Relevant HC_nH Chain Family: An Attempt to Aid Astronomical Observations