High-accuracy estimates for the vinylidene-acetylene isomerization energy and the ground state rotational constants of:C=CH2

Hyunwoo Lee, Joshua H. Baraban, Robert W. Field, John F. Stanton

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Highly accurate calculations are reported for properties of vinylidene (H2C=C:), specifically the position of its zero-point vibrational level relative to that of acetylene and its equilibrium structure and ground state rotational constants. The isomerization energy of vinylidene calculated at the HEAT-456QP level of theory is 43.53 ± 0.15 kcal mol-1, in agreement with the previous best estimate, but associated with a much smaller uncertainty. In addition, the thermochemical calculations presented here also allow a determination of the H2CC-H bond energy of the vinyl radical at the HEAT-345(Q) level of theory, which is 77.7 ± 0.3 kcal mol -1. The equilibrium structure of vinylidene, estimated with an additivity scheme that includes treatment of correlation effects beyond CCSD(T) as well as relativistic and adiabatic (diagonal Born-Oppenheimer correction) contributions, is rCC = 1.2982 ± 0.0003 Å, r CH = 1.0844 ± 0.0003 Å, and θCCH = 120.05 ± 0.05, with zero-point rotational constants (including vibrational contributions and electronic contributions to the moment of inertia) estimated to be A0 = 9.4925 ± 0.0150 cm-1, B 0 = 1.3217 ± 0.0017 cm-1, and C0 = 1.1602 ± 0.0016 cm-1.

Original languageEnglish
Pages (from-to)11679-11683
Number of pages5
JournalJournal of Physical Chemistry A
Volume117
Issue number46
DOIs
StatePublished - 21 Nov 2013
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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