First high resolution study of the pentad bending bands of deuterated silane: Energy structure of the (0200), (0101) and (0002) vibrational states of (SiD4)-Si-28, (SiD4)-Si-29 and (SiD4)-Si-30

The infrared spectra of SiD4 in natural abundance were measured in the region of 350-2050 cm(-1) with a Bruker IFS 125HR Fourier transform interferometer at an optical resolution of 0.0021 and 0.0016 cm(-1) and analyzed. Not less than 6490 transitions with J(max) = 33 were assigned for the first time to the bands 2v(4), v(2)+ v(4), and 2v(2) of the (SiD4)-Si-28 molecule. Numerous ``hot'' dyad-pentad transitions (in general, 5545 ``hot'' transitions) were also assigned for the first time in the region of 600-760 cm(-1). Rotational, centrifugal distortion, tetrahedral splitting, and interaction parameters for the (0002, F-2), (0002,E), (0002,A(1)), (0101, F-2), (0101, F-1), (0200, A(1)) and (0200, E) vibrational states were determined from the fit of experimental line positions. The obtained set of 69 fitted parameters reproduces the initial experimental data with an accuracy of d(rms) = 3.12 x 10(-4) cm(-1) for the 6490 ``cold'' transitions and d(rms) = 2.33 x 10(-4) cm(-1) for the 5545 ``hot'' transitions. Results of the analogues analysis for the (SiD4)-Si-29 and (SiD4)-Si-30 isotopologues with 403/136 ``cold'' and 171/99 ``hot'' assigned transitions are presented also. (C) 2021 Elsevier Ltd. All rights reserved.