P. Rodziewicz

Unusual spectroscopic properties of CF3H dissolved in liquified Ar, N2, CO, and CO2

Abstract The FTIR spectra of CF 3 H have been studied in liquefied Ar, N 2 , CO, and CO 2 . The effect of a blue shift of frequency of the C – H stretching vibration accompanied by a decrease in the integral intensity of the corresponding ν 1 band was found in the studied series of solvents. The combination bands ascribed to simultaneous excitation of vibrations of interacted molecular partners have been revealed in CO and CO 2 solutions. DFT/B3LYP and ab initio MP2 calculations utilizing the 6-311++G(3df,3pd) basis set suggest weak linear F 3 CH⋯ B complex formation, reproduce the experimentally observed unusual trends for B= Ar , N 2 , CO, CO 2 , and predict the conventional red frequency shift of the ν 1 band for B =NH 3 .

Degeneracy Lifting Effect in the FTIR Spectrum of Fluoroform Trapped in a Nitrogen Matrix. An Experimental and Car-Parrinello Molecular Dynamics Study.

The FTIR spectra of fluoroform trapped in argon and nitrogen matrixes are studied at T ∼ 10-30 K. The bands of E symmetry show the splitting effect in a nitrogen matrix, which is absent in an argon matrix. The effect is the most prominent in the case of the ν4 CH bending vibration. It decreases slightly with increasing temperature. Both static and Car-Parrinello molecular dynamic simulations suggest that the degeneracy lifting is due to C3v symmetry lowering caused by interactions between fluoroform and all neighbor N2 matrix molecules.

CH⋯B interactions in acetylene containing solutions: experimental and theoretical DFT studies

Abstract Weak to medium H-bonded interactions of the CH⋯B type (B=CS 2 and N(CD) 5 ) have been studied in C 2 H 2 /B mixtures. The spectral characteristics (frequency, width, and absolute integral intensity) of the CH asymmetric stretching band of acetylene were determined. Analogously to C 2 H 2 /CO 2 system studied earlier, in the case of CS 2 solutions, the combination bands ascribed to simultaneous excitations of vibrations of interacted CS 2 and C 2 H 2 molecular partners have been found. The observed spectroscopic features have been compared with the results of theoretical DFT/B3LYP calculations utilizing the 6-311++G(3df, 3pd) basis set. They predict 1:1 and 1:2 complex formations with the linear H-bonded structure in the case of N(CD) 5 and nonlinear weakly bounded structures in the case of CS 2 . The results obtained suggest predomination of 1:1 complexes of acetylene with pyridine in Xe and CS 2 solutions at conditions studied.