High-Resolution Laser Spectroscopy of CaS:  Deperturbation Analysis of the AΣ⁺−X¹Σ⁺ Transition

Abstract

The A 1 Σ + -X 1 Σ + electronic transition in CaS has been rotationally analyzed using high-resolution, laser excitation spectroscopy. Doppler-limited spectra were recorded for the 0-0, 1-0, 1-1, 2-1, 3-1, 3-2, 4-2, 4-3, 5-3, 5-4, 6-4 and 6-5 bands with a measurement precision of approximately 0.003 cm -1 . In total, more than 1200 line positions have been measured, assigned and employed in least-squares fits of molecular parameters. The A 1 Σ + state is extensively perturbed and level crossings have been identified and analyzed in the A 1 Σ + υ ) 3, 4, 5, and 6 vibrational levels. The perturbations are believed to arise from interactions of the A 1 Σ + state with the a 3 Π and A′ 1 Π states. Term values and effective rotational parameters for the perturbing states are obtained through a partial deperturbation analysis of the perturbed bands. Estimated values of the principal molecular parameters are T 00 ) 15194.428(2) cm -1 , R e ′ ) 2.38626(16) Å, and ω e ′ ) 409.077(9) cm -1 for the A 1 Σ + state, and R e ′′ ) 2.31770(14) Å and ω e ′′ ) 462.273(12) cm -1 for the X 1 Σ + state.

Applying ab initio Calculations to Theoretically Investigate the Electronic Structure of the Calcium Sulfide Molecule CaS

“…The results, presented in Table 1, have been compared to those available in previous theoretical and experimental studies (Blues & Barrow, 1969) (Marcano & Barrow, 1970) (Partridge, Langhoff, & Bauschlicher, 1988) (Takano, Yamamoto, & Saito, 1989) (Jarman, Hailey, & Bernath, 1992) (Andersson & Davis, 2001) (Melville & Coxon, 2002). The molecular spectroscopic constants of CaS, computed here, show good agreement with the investigations found in earlier literature, especially when linked to prior experimental outcomes.…”

“…Andersson and Davis studied the singlet X 1 Σ + and (2) 1 Σ + states of CaS by a Fourier Transform Spectrophotometer and calculated the corresponding principal molecular constants (Andersson & Davis, 2001). The same 2 states were also inspected again using high-resolution laser excitation spectroscopy by Melville & Coxon (Melville & Coxon, 2002). sulfide, in the 2s+1 Λ ± representation, by means of the complete active space self-consistent field (CASSCF) and the multi-reference configuration interaction (MRCI) with Davidson correction (+Q) computational approaches.…”

High-resolution laser spectroscopy of YbS: Deperturbation analysis of the A0+–X0+ transition

“…While many lanthanide monoxides and monofluorides have been studied using laser spectroscopy, and by a variety of theoretical techniques, there are very few examples of spectroscopic studies for other small gas-phase molecules containing a lanthanide atom. Some examples of recent work, however, on ytterbium diatomic and polyatomic molecules include laser spectroscopic studies of YbCl, 3 YbBr, 4 YbOH/OD, 5 and YbCCH. 6 Ytterbium-containing molecules have attracted the majority of attention experimentally owing to their similarity with the corresponding alkaline-earth metal species.…”