W. Jastrzebski

A full analytic potential energy curve for the aΣ+3 state of KLi from a limited vibrational data set

Fourier transform spectra of near-infrared laser-induced fluorescence in (39)K(6)Li show transitions to high vibrational levels of both the X (1)Sigma(+) and a (3)Sigma(+) electronic states. These include 147 transitions into six vibrational levels of the a (3)Sigma(+) state, which lie between 7 and 88 cm(-1) below the dissociation asymptote. Unfortunately, their energies span less than 30% of the well depth. However, fitting those data to eigenvalues of analytical model potential functions whose outer limbs incorporate the theoretically predicted long-range form, V(R) approximately D-C(6)R(6)-C(8)R(8), yields complete, plausible potential curves for this state. The best fits converge to remarkably similar solutions which indicate that D(e)=287(+/-4) cm(-1) and R(e)=4.99(+/-0.09) A for the a (3)Sigma(+) state of KLi, with omega(e)=47.3(+/-1.4) and 44.2(+/-1.5) cm(-1) for (39)K(6)Li and (39)K(7)Li, respectively. Properties of the resulting potential are similar to those of a published ab initio potential and are consistent with those of the analogous states of Li(2), K(2), Na(2), and NaK.

THEORETICAL STUDY OF THE ELECTRONIC STRUCTURE OF KLI AND COMPARISON WITH EXPERIMENTS

Abstract Potential energy curves have been calculated for 58 electronic states of KLi using non-empirical one-electron pseudopotentials, polarisation potentials and full-valence configuration interaction calculations. To the best of our knowledge, the present theoretical data are the first available ones for excited states of KLi. Comparisons with our previously published Rydberg–Klein–Rees curves and experimental spectroscopic constants are presented showing an overall good agreement. A long-range description for both the (1) 1, 3 Σ + states is proposed.

The molecular constants and potential energy curve of the D1Π state in KLi

Polarisation labelling spectroscopy has been used to record the excitation spectrum of KLi in the region 18 500 to 20800cm−1. Transitions are observed to all bound levels of the D1Π state, and to some high vibrational levels of the C1Σ+ state, both of which dissociate to K(4S) + Li(2P) atoms. Spectroscopic constants are given for both electronic states. A pointwise potential curve is constructed for the D1Π state, which has a small barrier (26.5cm−1) to dissociation, located at 7.79 A.

A regularized inverted perturbation approach method: Potential energy curve of the 4 1Σu+ state in Na2

We describe a modification of the inverted perturbation approach method allowing to construct physically sensible potential energy curves for electronic states of diatomic molecules even when some parts of the potential are not adequately characterized by the experimental data. The method is based on a simple regularization procedure, imposing an additional constraint on the constructed potential curve. In the present work it is applied to the double minimum 4 (1)Sigma(u) (+) state of Na(2), observed experimentally by polarization labeling spectroscopy technique.

Experimental study of the 61Π and 71Π states of NaK by polarization labeling spectroscopy technique

Abstract The polarization labeling spectroscopy technique is used to study the 6 1 Π ←X 1 Σ + and 7 1 Π ←X 1 Σ + band systems of the NaK molecule located in the UV range. For both excited states accurate molecular constants are derived which describe the 6 1 Π state to 68% and the 7 1 Π state to 71% of their potential well depths. The parameters deduced from the experiment are compared with the recent theoretical calculations.

Reanalysis of the A 1 Sigma +u state of Na2 by polarization labelling spectroscopy

The polarization labelling spectroscopy technique is applied to study the A ¹Σu + – X ¹Σg + band system of sodium dimer. Six visible lines of an argon ion laser are used to label rovibronic levels in the ground state of Na2. Rotationally resolved polarization spectra are observed in the range 14200–17600 cm-1. A set of Dunham coefficients is deduced to fit all unperturbed levels of the A ¹Σu + state with 0 ⩽ ν ⩽ 43 and 12 ⩽ J ⩽ 126.

Spectroscopic study of the E(4)1Σ+ state in NaLi

Polarization labelling spectroscopy is applied to study the excited E1sigma+ state of NaLi in the energy range 26,500-28,000 cm(-1) above the bottom of the ground state. The potential curve of the E state is constructed using the Inverted Perturbation Approach method. The values of Te, omega(e) and Re are found to be 26,474.82(4), 180.3(2) cm(-1) and 3.343(1) A, respectively.

The C(2)1Πu state of Na2 molecule studied by polarization labelling spectroscopy method

The C1pi(u) <-- X1sigma(g)+ system of Na2 is studied by the polarization labelling spectroscopy technique. Accurate molecular constants are derived for the observed levels nu = 0-12, J = 12-100 in the C1pi(u) state.

The potential energy barrier of the 2Π1 state in KLi

The polarisation labelling spectroscopy technique has provided detailed information about the shape of the potential barrier to dissociation of the 2(1)Pi state in KLi. The potential curve of the 2(1)Pi state is constructed using the Inverted Perturbation Approach method. Our analysis shows that the barrier height is DeltaE=20.8+/-1.0 cm(-1) relative to the dissociation limit and the barrier maximum is located at Rbar=8.2+/-0.1 A.

Experimental long range potential of the BΠ1 state in NaRb

The long range potential of the B 1Pi state in NaRb has been investigated by observation of rovibrational levels that it supports, including the high lying ones, with the technique of polarization labeling spectroscopy. This has allowed us to characterize the potential energy curve up to 1.9 cm(-1) from the dissociation limit. The highest observed rovibrational level v=49, J=10 has the outer turning point at R=16.48 A.