First high–resolution analysis of the fundamental bands of ²⁹SiD₄ and ³⁰SiD₄: Line positions and strengths

The high resolution infrared spectra of ^MSiD₄ (M=29,30) in natural abundance of ^MSi (92.23% of ²⁸Si, 4.68% of ²⁹Si, and 3.09% of ³⁰Si) were measured with Bruker IFS120 and IFS125 HR Fourier transform infrared spectrometers at an optical resolution between 0.00096 and 0.0025 cm−1 and analyzed in the regions of 550–800 cm−1 and 1480–1700 cm−1 where the four fundamental bands, ν₂, ν₄, ν₁ and ν₃ are located. The 840/1641/888 transitions with J^max. = 31/31/35 and 638/1356/838 transitions with J^max. = 31/31/34 were assigned to the ν₂, ν₄, and ν₃ bands of ²⁹SiD₄ and ³⁰SiD₄. The subsequent weighted fit of experimentally assigned transitions was made with the Hamiltonian model which takes the resonance interactions between pairs of vibrational states (0010, F₂)/(1000, A₁) and (0001, F₂)/(0100, E) into account. As a result, sets of 22 and 22 fitted parameters were obtained which reproduces the initial 3369 and 2832 ro–vibrational transitions of the ²⁹SiD₄ and ³⁰SiD₄ isotopologues with the drms=2.34×10⁻⁴ cm−1 and 2.67×10⁻⁴ cm−1, respectively. An analysis of 221 and 134 experimental ro–vibrational lines of the ν₄/ν₂ and ν₃ bands of ²⁹SiD₄ and ³⁰SiD₄ was performed using the Hartmann–Tran profile to simulate the measured line shape and to determine experimental line intensities. A detailed line list of transitions of ²⁹SiD₄ and ³⁰SiD₄ in the studied regions is generated.