Spectroscopy of small boron-containing molecules and line intensity calculations for HCl and CaH

The Fourier-transform infrared emission spectra of BO were recorded. The observed spectrum of BO in the 1200 - 2100 cm-1 region contains three bands: the fundamental bands of 11BO and 10BO and a hot band of 11BO with band origins measured to be 1861.9242(97), 1915.3071(09) and 1838.3773(68) cm-1, respectively.
The infrared spectra of the unstable HBS molecule in the ν_1 and ν_3 fundamental regions have been recorded at high resolution using a Fourier transform spectrometer. Total 35 bands involving 45 vibrationally exited states located up to 6000 cm-1 above the ground state were assigned for H11/10B32S.
A dipole moment function (DMF) for hydrogen chloride (HCl) has been obtained using a direct fit approach. Combining wavefunctions derived from the Rydberg-Klein-Rees (RKR) numerical method and a semi-empirical DMF, line intensities were calculated numerically for bands with Δv=0,1,2,3,4,5,6,7 up to v′=7.
Einstein A coefficients and absolute line intensities have been calculated for the E2Π-X2Σ+ transition of CaH. Using wavefunctions derived from the RKR method and electronic transition dipole moment functions obtained from high-level ab initio calculations, rotationless transition dipole moment matrix elements have been calculated for all 10 bands involving v´=0,1 of the E2Π state to v˝=0,1,2,3,4 of the X2Σ state. The rotational line strength factors (Hönl-London factors) are derived for the intermediate coupling case between Hund’s case (a) and (b) for the E2Π-X2Σ+ transition.
High-resolution spectra of BaS were recorded using laser excitation spectroscopy. The observed rotationally-resolved spectrum of BaS in the 12100-12765 cm-1 spectral range contains the 2-1, 3-1, 3-2, 4-2, 5-2, 5-3 vibrational bands of the A'1Π - Χ1Σ+ transition and the 4-1, 5-1, 5-2 vibrational bands of the a3Π1 - X1Σ+ transition. Approximately 1000 lines of the A'1Π - Χ1Σ+ transition and 600 lines of the a3Π1 - X1Σ+ transition for the main isotopologue 138Ba32S (67.5% natural abundance) were measured. Rotational and vibrational parameters were derived for the A'1Π and a3Π1 states.