Vibrational spectra and force constants of symmetric tops: Rovibrational spectra in the ν3 region of monoisotopic species of H 3GeCl, H 3GeBr, and H 3GeI
The gas phase infrared spectra of several monoisotopic species of H 3GeCl, H 3GeBr, and H 3GeI have been recorded in the ν3 region near 420, 300, and 250 cm -1, respectively, with a resolution between 0.03 and 0.04 cm -1. Rotational J structure of the fundamental and of several "hot" bands of ν3 has been resolved and analyzed by means of polynomial methods. The K structure of J clusters is indicated, and α3A values were estimated from a band contour simulation. The molecular parameters ν30, χ33, ( B3- B0), and DJ were determined for several isotopic combinations. The ν3 and 2 ν3 levels are apparently unperturbed except for H 3Ge 35Cl species for which Fermi resonance between 2 ν3 and ν2 has been established.