Equilibrium molecular structures of vinyl carbon chains: Vinyl acetylene, vinyl diacetylene, and vinyl cyanide

Extending the Applicability of the Semi-experimental Approach by Means of “Template Molecule” and “Linear Regression” Models on Top of DFT Computations

“…The r e SE structures of t -ACR and c -ACR have been taken from ref ( 56 ) and those of t -GL have been taken from ref ( 70 ); they are also available in the SE database 29 together with the r e SE of t -BD. Those of VC and VAC were evaluated in ref ( 31 ) and that of Z -PGIM has been purposely determined in this work using the data from refs ( 54 ) and ( 71 ). For Z -PGIM, the availability, in addition to the rotational constants of the parent isotopologues, of the data for the three 13 C isotopic species and two deuterated variants (at the −NH and −CCH sites) has enabled a reliable, even if partial, determination of the SE equilibrium structure.…”

“…The difference SE( B e SE ) – SE( r e SE ) is reported within parentheses. d SE( B e SE ) using vibrational corrections at the fc-CCSD(T)/cc-pVTZ level [from ref ( 31 ) for VAC and VC, from ref ( 56 ) for ACR ( trans and cis ), and from ref ( 70 ) for t -GL]. The difference SE( B e SE ) – SE( r e SE ) is reported within parentheses.…”

Rotational spectroscopy of singly 13C substituted isotopomers of propyne and determination of a semi-empirical equilibrium structure

“…Only the methyl group in propyne can be involved in the delocalization of the π electrons of the CC triple bond, which leads to a triple bond length of 120.46 pm, between the acetylene and diacetylene values, and to a single bond length of 145.88 pm, between the diacetylene and the ethane values. The degree of delocalization is larger in vinyl acetylene than in propyne, leading to CC triple and single bond lengths closer to those of diacetylene [73]. The acetylenic CH bond lengths in Table 4 are all very close to 106.15 pm; slightly larger scatter exists for the given methylenic CH bond lengths.…”

High-resolution infrared study of vinyl acetylene: The ν13 (214 cm−1) and ν18 (304 cm−1) fundamentals

“…Parameter is kept fixed in the fit if no error is specified. a A, B, and C rotational constants are calculated from the ae-CCSD(T)/cc-pwCV5Z equilibrium structure [10] and zero-point vibrational corrections obtained at the fc-CCSD(T)/ANO2 level of theory. Note.…”

“…Refs. [3][4][5]) has been studied from the microwave into to the submillimeter regime reaching frequencies as high as 790 GHz [4,[6][7][8][9][10]. Vibrational satellites from the energetically low-lying first and even multiply This paper is dedicated to Prof. Dr. Stephan Schlemmer, on the occasion of his 60th birthday.…”