Eur. Phys. J. D 48, 177-185 (2008)
https://doi.org/10.1140/epjd/e2008-00089-y

The B¹Π and D¹Π states of LiCs studied by Fourier-transform spectroscopy^*

¹ Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
² Department of Physics, Sofia University, 5 James Bourchier Boulevard, 1164 Sofia, Bulgaria

Corresponding author: ^a Stein@iqo.uni-hannover.de

Received: 5 February 2008
Revised: 3 April 2008
Published online: 7 May 2008

Abstract

We report on a high resolution study of two excited electronic states of the LiCs molecule, namely the B¹Π and the D¹Π. The experimental data are derived from the Fourier transform spectroscopy on the ground states X¹Σ⁺ and a³Σ⁺ [Phys. Rev. A 75, 042513 (2007)]. Along with the laser induced fluorescence also collisionally induced satellites are observed, which expand the data sets for the B¹Π and D¹Π states. The lower state, B¹Π, is found to be free of significant local perturbations, although a strong dependence of the Λ-doubling on the vibrational and the rotational quantum numbers indicates a noticeable influence of the nearby ¹Σ⁺ states. A set of Dunham coefficients and a potential energy curve for this state are derived. In contrast, the energy levels of both the e and f parities of the D¹Π state were found to be strongly perturbed, making a precise description within a single channel model impossible. Nevertheless we present an approximated experimental potential energy curve which can be applied in a further deperturbation analysis. We discuss the prospects of these electronic states for the formation of cold LiCs molecules in a magneto-optical trap of mixed species.