Semispectroscopic and Quantitative Structure−Property Relationship Estimates of the Equilibrium and Vibrationally Averaged Structure and Dipole Moment of 1-Buten-3-yne

Abstract

Systematic quantum chemical calculations have been performed to obtain precise estimates of the equilibrium and vibrationally averaged molecular structure and electric dipole moment of vinylacetylene (VA, 1-buten-3-yne). Anharmonic (cubic and semi-diagonal quartic) MP2/cc-pVTZ force fields in normal coordinates were computed to account for anharmonic vibrational effects, including zero-point contributions to the rotational constants and the electric dipole moment. A simultaneous weighted least-squares structural refinement was performed, resulting in the best semispectroscopic estimate of the r e structure of VA. The refinement was based on experimentally measured ground-state rotational constants of two isotopologs of VA corrected to equilibrium values using MP2/cc-pVTZ vibration-rotation interaction constants and all-electron CCSD(T)/ aug-cc-pVTZ structural constraints. The semispectroscopic r e structure of VA agrees excellently with the high-level CCSD(T)/aug-cc-pVTZ ab initio structure. The most dependable, CCSD (

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

“…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.…”