Conformational effects in the vibrational and electronic spectra of propionaldehyde: Experimental and theoretical studies.

Autor:	Sharma N; Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India., Shastri A; Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India., Das AK; Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India., Rajasekhar BN; Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
Jazyk:	angličtina
Zdroj:	The Journal of chemical physics [J Chem Phys] 2023 Oct 14; Vol. 159 (14).
DOI:	10.1063/5.0169630
Abstrakt:	We report here investigations on conformational effects in the vibrational and electronic spectra of the propionaldehyde (propanal) molecule using FTIR (600-3200 cm-1) and vacuum ultraviolet (VUV) synchrotron radiation photoabsorption (52 500-85 000 cm-1) spectroscopy respectively. Detailed theoretical calculations (using DFT and TDDFT methodologies) on ground and excited states of the cis and gauche conformers of propanal are performed; a comprehensive spectral analysis of the IR and VUV spectra is presented. A reinvestigation of the IR spectrum reveals several new bands assigned to the gauche conformer based on theoretical calculations. The VUV spectrum exhibits rich Rydberg series structure assigned to ns, np and nd series converging to the first ionization potentials of the two conformers. Earlier assignments of the 3s cis and gauche origins are revised in addition to extending Rydberg series analysis to several higher members. Vibronic bands accompanying the 3s, 4s and 4p Rydberg states are assigned using estimated vibrational frequencies of cis and gauche conformers in the cationic ground state. Simulated potential energy curves of the first few excited states (singlets and triplets) of cis and gauche conformers of propanal help in gaining insights into photodissociation mechanisms and possible conformational effects therein. (© 2023 Author(s). Published under an exclusive license by AIP Publishing.)
Databáze:	MEDLINE
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