Vibrational Dynamics of Crystalline 4-Phenylbenzaldehyde from INS Spectra and Periodic DFT Calculations

authors	Nolasco, MM; Araujo, CF; Vaz, PD; Amado, AM; Ribeiro-Claro, P
nationality	International
journal	MOLECULES
author keywords	inelastic neutron scattering; density functional theory; vibrational assignment; molecular crystal; torsional potential; C-H center dot center dot center dot O hydrogen bonds
keywords	INELASTIC NEUTRON-SCATTERING; DOT-O INTERACTIONS; HYDROGEN-BOND; FLUORESCENCE-SPECTRA; MOLECULAR-CRYSTALS; RAMAN; ROTATION; IR; SPECTROSCOPY; S-0
abstract	The present work emphasizes the value of periodic density functional theory (DFT) calculations in the assessment of the vibrational spectra of molecular crystals. Periodic calculations provide a nearly one-to-one match between the calculated and observed bands in the inelastic neutron scattering (INS) spectrum of crystalline 4-phenylbenzaldehyde, thus validating their assignment and correcting previous reports based on single molecule calculations. The calculations allow the unambiguous assignment of the phenyl torsional mode at ca. 118-128 cm(-1), from which a phenyl torsional barrier of ca. 4000 cm(-1) is derived, and the identification of the collective mode involving the antitranslational motion of CH...O bonded pairs, a hallmark vibrational mode of systems where C-H...O contacts are an important feature.
publisher	MDPI
isbn	1420-3049
year published	2020
volume	25
issue	6
digital object identifier (doi)	10.3390/molecules25061374
web of science category	Biochemistry & Molecular Biology; Chemistry, Multidisciplinary
subject category	Biochemistry & Molecular Biology; Chemistry
unique article identifier	WOS:000530248700117