Supersonic jet cooled rotational spectrum of 2,4-difluorophenol

• Published in: Journal of molecular spectroscopy 2017-05, Vol.335, p.23-26
• Main Authors: Nair, K.P. Rajappan, Dewald, David, Wachsmuth, Dennis, Grabow, Jens-Uwe
• Format: Article
• Language: English
• Subjects: 2,4-Difluorophenol; Microwave spectroscopy; Molecular structure; Rotational spectrum; Supersonic jet
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1016/j.jms.2017.01.003

2H nuclear quadrupole hyperfine structure in C6H3F2OD. [Display omitted] •Supersonic jet cooled rotational spectrum of 2,4-difluorophenol has been studied.•Eight isotopic species of the molecule have been investigated along with the parent molecule.•Substitution structure of the molecule has been determined.•Deuterium nuclear hyperfine structure and the quadrupole coupling constants in the deuterium species have been determined.•Experimental study is substantiated with ab initio and density functional calculations. The microwave spectrum of the cis form of aromatic 2,4-difluorophenol (DFP) has been recorded and analyzed in the frequency range of 5–25GHz using a pulsed-jet Fourier transform microwave spectrometer. Rotational transitions were measured for the parent and all unique single 13C substituted isotopologues and 18O in natural abundance and on enriched deuterium species on the hydroxyl group. The rotational (MHz), centrifugal distortion (kHz), and quadrupole coupling constants (MHz) in deuterium species were determined. The rotational constants for the parent species are obtained as A=3125.04158(43)MHz, B=1290.154481(54)MHz, C=913.197424(36)MHz, DJ = 0.020899(162)kHz, DK=0.9456(100)kHz, DJK=0.09273(65)kHz, d1=−0.00794(14)kHz, d2=−0.002356(93)kHz and for the deuterated species A=3125.38579(44)MHz, B=1261.749784(48)MHz, C=898.927184(27)MHz, DJ = 0.02096(19)kHz, DK=0.379(74)kHz, DJK=0.0880(11)kHz, d1=−0.00691(11)kHz, d2=−0.00183(11)kHz. The deuterium quadrupole coupling constants are χaa=−0.0109(33)MHz, and (χbb−χcc)=0.2985(59)MHz. The rs substitution structure was determined using the measured rotational constants of the isotopologues, a nonlinear least squares fit was performed to obtain the best fit gas phase r0 effective structure. Supporting ab initio (MP2) and density functional calculations provided consistent values for the rotational parameters, and molecular structure.