CCSD(T)-F12 calculations of the IR spectrum of cyanoacetylene HC3N beyond the harmonic approximation

• Published in: Chemical physics letters Vol. 754; p. 137746
• Main Authors: Dargelos, Alain, Pouchan, Claude
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2020; Elsevier
• Subjects: Ab-initio CCSD(T) and CCSD(T)-F12 calculations; Chemical Sciences; Cyanoacetylene molecule; IR spectroscopy; Cyanoacetylene molecule; IR spectroscopy; Ab-initio CCSD(T) and CCSD(T)-F12 calculations; Ab-initio CCSD(T) and CCSD(T)-F12 calculations, cyanoacetylene molecule, IR spectroscopy
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2020.137746

[Display omitted] •It is the first complete theoretical study of the IR spectrum of HC3N.•We propose an ab-initio spectrum with the assignment of all bands. The high-resolution infrared spectrum of HC3N has been the subject of numerous experimental studies. However, none of these studies has been based on high-quality theoretical work. On the basis of an anharmonic potential CCSD(T)-F12/aug-cc-pVTZ and the use of a pure variational method (VCI) the IR spectrum of HC3N was calculated between 200 and 4800 cm−1. These calculations make it possible, on the basis of the positioning of the bands and the calculation of their intensity, to revisit the entire IR spectrum and to assign a large part of it, overtones, combinations bands and hot bands to the experimental observations.