The BΠ1 state of NaCs: High resolution laser induced fluorescence spectroscopy and potential construction

Abstract

The lowest (1)Pi state of the NaCs molecule, the B(1)(1)Pi state, was studied using a dye laser for inducing fluorescence that was resolved by a high resolution Fourier-transform spectrometer. The presence of argon buffer gas yielded rich rotational relaxation spectra allowing to enlarge the data set for the B(1)(1)Pi state, to obtain Lambda-splittings and to reveal numerous local perturbations. 543 weakly perturbed energy levels for rotational quantum numbers from J(')=5 to 168 and vibrational quantum numbers from v(')=0 to 25, which cover about 87% of the potential well depth, were used for a direct pointwise fit of the potential energy curve applying the inverted perturbation approach method. The resulting potential reproduces the term values for v(')=0-7 with an experimental accuracy of about 0.01-0.02 cm(-1), whereas for v(')=8-25 the deviations increase due to the perturbations, going to the order of 1 cm(-1); an extrapolation is made to the dissociation asymptote.

Spin-forbiddenc3Σ+(Ω=1)←Grochola1, Kowalczyk2, Szczepkowski3 et al. 2011Phys. Rev. A241130View full textAdd to dashboardCite

“…Only five states have been characterized, namely the two lowest states, X 1 + and a 3 + [1,2], and three excited states, B(1) 1 , D(2) 1 , and 3 1 [1,[3][4][5][6]. Further spectroscopic studies on additional electronic states are necessary to complete our understanding, to test ab initio theoretical predictions, and to facilitate experiments on the formation of ultracold NaCs molecules [7][8][9][10][11].…”

Calculation of spectroscopic constants and radiative parameters for the B 1Π-X 1Σ+ electronic transitions of NaK, NaRb, and NaCs molecules

“…The first row gives the values calculated based on the potential curve; the second row presents the experimental data for NaK [23], NaRb [21], and NaCs [24]; * indicates calculations by the Kratzer formula with the use of experimental data; and ** indicates calculations by the Kemble formula with the use of experimental data.…”

“…The parameters of function (2) are obtained by the least squares method using turning points of the RKR potential curves and the experimental values of the dissociation energy. The parameters of the PM and RKR potential functions are calculated using the experimental vibrational and rotational spectroscopic constants from [21,23,24]. Figure 1 shows the poten tial curves for the B 1 Π excited states of NaK, NaRb, and NaCs molecules plotted using the calculated parameters.…”

“…To calculate the wavenumbers, we used the values of (B 1 Π) from [22][23][24]. Energies and and corresponding wave functions and were found from the numerical solution of the radial wave equation using the effective potential (14) where μ is the reduced molecular mass.…”

“…Detailed analysis of the elec tronic spectra of the B 1 Π-X 1 Σ + transition in NaK, NaRb, and NaCs molecules is carried out using laser methods and high resolution techniques. Molecular constants necessary for constructing semiempirical potential curves of the ground and excited states of the B 1 Π-X 1 Σ + electronic transition of NaK, NaRb, and NaCs molecules were found in [19][20][21][22][23][24].…”