Comprehensive study of the pentad bending triad region of germane: Positions, strengths, widths and shifts of lines in the 2 nu(2), nu(2) + nu(4) and 2 nu(4) bands of (GeH4)-Ge-70, (GeH4)-Ge-72, (GeH4)-Ge-73, (GeH4)-Ge-74, (GeH4)-Ge-76

The high resolution infrared spectra of GeH4 in its natural abundance were recorded with a Bruker IFS125 HR Fourier transform infrared spectrometer at an optical resolution of 0.003 cm(-1) and analyzed in the region of 1400-2000 cm(-1) where the first bending overtone 2.2, 2.4 and combinational nu(2) +nu(4) bands are located. Ro-vibrational line positions and energies of the (GeH4)-Ge-70 species were analysed for the first time and line positions and energies of the (GeH4)-Ge-72 and (GeH4)-Ge-74 species were improved considerably in comparison with the preceding studies. The numbers of 2316/2406/873/3007/2257 transitions with J(max) = 21/23/18/22/19 of the 2.2 (A(1-) and E-type sub-bands), 2 nu(4) (A(1) -, E- and F-2 -type sub-bands) and nu(2) +nu(4) (F-1- and F-2-type sub-bands) bands of the (GeH4)-Ge-70, (GeH4)-Ge-72, (GeH4)-Ge-73, (GeH4)-Ge-74, and (GeH4)-Ge-76 molecules were used in the joint weighted fit of experimentally assigned transitions with the Hamiltonian model which takes the resonance interactions between the seven, (0200, A(1)), ( 0200, E), (0101, F-1), (0101, F-2), (0002, A(1)), ( 0002, E) and (0002, F-2), vibrational states into account. From our preceding studies 5563 hot band transitions were also taken into account. As the result of a joint fit, a set of 129 fitted parameters was obtained which reproduce the initial 16422 experimental (including ``hot'') transitions of five isotopologues with the d(rms) = 3.26 x10(-4) cm(-1). A line strength analysis of the 1697 experimentally recorded transitions of all species was made by the fit of their line shapes with the Hartmann-Tran profile and 13 effective dipole moment parameters were obtained from the weighted fit which reproduce the initial experimental line strengths with the d(rms) = 3.4%. Self-broadening coefficients of 993 lines and self-shift coefficients of 674 lines were determined from the multi-spectrum analysis of these lines. (c) 2021 Elsevier Ltd. All rights reserved.