High-Resolution Spectrum and Rovibrational Analysis of the ν2/ν5 Dyad of D3SiF near 700 cm−1

✍ Scribed by M. Badaoui; N.Ben Sari-Zizi; G. Graner; E.B. Mkadmi; H. Bürger; P. Pracna

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 380 KB
• Volume: 200
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1999.8021

✦ Synopsis

The (\nu_{2}\left(A_{1}, 710.157 \mathrm{~cm}^{-1}\right)) and (\nu_{5}\left(E, 701.717 \mathrm{~cm}^{-1}\right)) fundamental bands of (\mathrm{D}{3}{ }^{28} \mathrm{SiF}) have been studied by FTIR spectroscopy with a resolution of (2.4 \times 10^{-3} \mathrm{~cm}^{-1}). We assigned 1648 lines for the parallel band ( (J{\max }=50, K_{\max }=21) ), 4279 for the perpendicular band (\left(J_{\max }=52, K_{\max }=27\right)), and in addition 671 perturbation-allowed transitions (\left(J_{\max }=50, K_{\max }=\right.) 12). The nearly degenerate (\mathrm{v}{2}=1) and (\mathrm{v}{5}=1) states are linked by ((\Delta K= \pm 1, \Delta l= \pm 1)) and ((\Delta K= \pm 2, \Delta l=\mp 1)) interactions, while the (l_{5}= \pm 1) levels of (\nu_{5}) interact also by (l(2,-1), l(2,2)), and (l(2,-4)) interactions. The first model with 36 free parameters, taking into account all these resonances through a nonlinear least-squares program, gave standard deviations of (1.56 \times 10^{-4} \mathrm{~cm}^{-1}) for 5997 nonzero-weighted IR data and (138 \mathrm{kHz}) for (8 \mathrm{MW}) data from the literature. The second model, in which the main Coriolis term was constrained to a force field value, used 37 parameters and gave similar standard deviations. A new determination of the (A_{0}) and (D_{K}^{0}) ground state parameters was performed by two methods: either using differences between "forbidden" transitions differing by 3 in (K) or letting (A_{0}) and (D_{K}^{0}) free in the global fit. The values obtained are fully compatible with those obtained previously by the "loop method." ๑ 2000 Academic Press