Experimental study of the K2392Πg3 state by perturbation facilitated infrared-infrared double resonance and two-photon excitation spectroscopy

Abstract

The 39K2 2 3Pi(g) state has been observed by perturbation facilitated infrared-infrared double resonance and two-photon excitations. The vibrational numbering of the 2 3Pi(g) levels was determined by resolved fluorescence into the bound levels as well as to the continuum of the a 3Sigma(u)+ state. The rotational assignment of the 2 3Pi(g) levels excited by two-photon transitions was determined from excitation frequencies and resolved fluorescence into the bound levels of the a 3Sigma(u) + and b 3Pi(u) states. Molecular constants obtained from these observed levels agree with theoretical constants.

New experimental data on the K2 state analyzed with the multi-parameter approach

“…In our calculations, to begin with, we used the potential function of the 2 3 P g state determined in [27], the potential functions of the 3 3 P g and 4 3 R þ g states determined in [28], and the theoretical ab initio dipole moments of all the transitions under study computed in [26].…”

“…The new fluorescence transition wavelengths to the K 2 a 3 R þ u state were measured using the perturbation facilitated two-photon (one laser) double resonance scheme [2,3,6,27,35]. Ti:Sapphire ring laser (Coherent 899-29) was used to excite the molecules from thermally populated ground X 1 R þ g state ro-vibrational level to the 2 3 P g state via a mixed b $ A enhancing level, and the resolved fluorescence to the a 3 R þ u state was recorded with a SPEX 1404 double monochromator with an absolute accuracy of $0.2 cm À1 .…”

“…We have performed more recently additional experiments [27,28]. Our work reported in [27] was devoted to the observation and analysis of the K 2 2 3 P g state.…”

“…Our work reported in [27] was devoted to the observation and analysis of the K 2 2 3 P g state. A few new fluorescence spectra of transitions from this state to the lowest triplet state a 3 R þ u were registered there.…”

Theoretical investigation of the Ωg,u(+/−) states of K2 dissociating adiabatically up to K(4p P23/2)+K(4p P23/2)

“…The quality of these predictions was confirmed later by some new experimental investigations on excited states, mainly triplet states. [24][25][26][27][28][29][30][31] Our previous studies of the electronic structure of K 2 were performed under the assumption that spin-orbit effects could be neglected for this not too heavy alkali dimer. Nevertheless, including these effects should lead to a more precise description of the electronic structure of K 2 .…”