The stretching fundamental bands ν1, ν2 and ν4 of H28SiD3

The ν1(A1), Si-H stretching, ν2(A1) and ν4(E), Si-D stretchings, fundamental bands of HSiD3 have been recorded at an effective resolution of ca. 0.003 cm−1 between 2080 and 2280 cm−1 and between 1480 and 1720 cm−1, respectively. Ro-vibrational transitions of the H28SiD3 isotopologue have been assigned in the two spectral ranges, about 700 belonging to ν1, with J′ up to 25 and K up to 21, and about 1600 to the ν2/ν4 dyad, with J′ up to 24 and K′ up to 19. The spectra of all the bands evidence the existence of several perturbations. The transitions of ν1 have been analyzed either neglecting or including in the model A1/E Coriolis-type interactions with nearby dark states. The υ2 = 1 and υ4 = 1 states have been fitted simultaneously taking into account several ro-vibrational interactions between them and, in addition, with the υ5 = 2, l = 0 component, and with few other close dark states. The standard deviation of the fit for both ν1 and the ν2/ν4 dyad is, however, more than one order of magnitude larger than the estimated experimental precision and is independent on the adopted model.