B(1) ~1Π state of KCs: High-resolution spectroscopy and description of low-lying energy levels (Conference Paper)

摘要

The diode laser induced B(1) ~1Π → X ~1Σ ~+ fluorescence spectra of the KCs molecule were recorded by Fourier-transform spectrometer with resolution of 0.03 cm ~(-1). Buffer gas Ar was used to facilitate appearance of rotation relaxation lines in the spectra, thus enlarging the B(1) 1Π dataset, allowing one to determine the ∧-splitting constants and to reveal numerous local perturbations. A dataset was systematically obtained for B(1) ~1Π vibrational levels vv ′ ∈ [0; 5] nonuniformly covering rotational levels with J ′ ∈ [7; 233]. For v ′ ∈ [0; 3], the less-perturbed data of f-components were included in the fit. A pointwise potential energy curve (PEC) based on the inverted perturbation approach, as well as the Dunham coefficients, was obtained and compared with ab initio calculations; in particular, the energy of the PECs minimum T _e = 14 044.918(6) cm ~(-1) was determined. Both approaches allowed us to reproduce the vast majority of data used in the fit with accuracy of 0.02 cm ~(-1). Tentative molecular constants for several vibrational levels of the near lying C(3) ~1Σ ~+ state were estimated.