We report our determination of the molecular constants for the 21Π state of NaLi from a set of 732 spectral lines. Using the linear least-squares tting method, an optimum set of molecular constants, which corresponds to dimensionless root mean of squares of deviation σ = within cm−1 experimental uncertainty, have been derived. | Communications in Physics, Vol. 23, No. 2 (2013), pp. 135-138 MOLECULAR CONSTANTS OF THE 21 Π STATE OF NaLi MOLECULE NGUYEN TIEN DUNG, LE CANH TRUNG, DINH XUAN KHOA, AND NGUYEN HUY BANG Vinh University, 182 Le Duan Street, Vinh City, Vietnam E-mail: bangvinhuni@ Received 06 March 2013 ; revised manuscript received 25 April 2013 Accepted for publication 08 May 2013 We report our determination of the molecular constants for the 21 Π state of NaLi from a set of 732 spectral lines. Using the linear least-squares tting method, an optimum set of molecular constants, which corresponds to dimensionless root mean of squares of deviation σ = within cm−1 experimental uncertainty, have been derived. Abstract. I. INTRODUCTION The alkali-metal diatomic molecules with their main absorption bands in the UVVIS region are very appropriated for modern laser spectroscopy techniques. Experimental investigations for these molecules have further promoted since the emergence of molecular Bose-Einstein condensates (see [1] and references therein). As several experimental techniques related to cold molecules involve optical excitation either in the formation and/or detection stages, a precise spectroscopic characterization of excited molecular states is necessary. Among alkali-metal diatomic molecules NaLi is particularly interested because it is the lightest hetero-nuclear type and has permanent dipole moment, thus can be manipulated with external electric elds. Several experimental investigations for the 1 Σ+ and 1 Π symmetric types were performed to study up to the 91 Σ+ and 71 Π excited states [2-7]. Among those, the 21 Π state was still known only at vibrational resolution [4]. In this paper we determine the molecular constants for the 21 Π state of NaLi based our recent experimental data [8]. 1 Π STATE II. MOLECULAR CONSTANTS OF THE 2 The experimental data used in this work consist of 732 spectral lines in the 21 Π ← 11 Σ+ band. The data were obtained by .
