High-resolution laser excitation spectroscopy of the transition of BaOH

High-resolution laser spectroscopy of BaOH and BaOD: Anomalous spin-orbit coupling in the state

“…The recent high resolution analysis of theà 2 P ÀX 2 R þ transition of BaOH [9] yielded band heads for theà 2 P 1=2 ð0 0 0Þ ÀX 2 R þ ð0 0 0Þ andà 2 P 3=2 ð0 0 0Þ ÀX 2 R þ ð0 0 0Þ transitions at 11 484.286 and 12 046.933 cm À1 , respectively. High-resolution scans were performed based on these assignments to accurately locate the position of the two corresponding band heads for BaOD.…”

“…(4) refers to the e-(+) and f-parity (À) levels, respectively. The analysis was carried out using the same method utilised when fitting the three unidentified bands (U1-U3) in our previous analysis of theà 2 P ÀX 2 R þ transition of BaOH [9]. Table 3 illustrates the spectroscopic constants generated from the Hund's case (c) combined fits for theà 2 P 3=2 ð0 0 0Þ,à 2 P 1=2 ð0 0 0Þ andX 2 R þ ð0 0 0Þ states of BaOD.…”

“…The two band head positions previously assigned to theà 2 Pð0 0 0ÞÀ X 2 R þ ð0 0 0Þ transitions of BaOH [9] are a useful starting point in the search for the correspondingà 2 Pð0 0 0Þ ÀX 2 R þ ð0 0 0Þ bands of BaOD. The isotope shift caused by deuteration of BaOH was expected to be relatively small (e.g.…”

“…It is also interesting to compare the molecular constants generated in the least-squares fit using both the Hund's case (a) and Hund's case (c) expressions for the upper states in BaOH (Ref. [9]) and BaOD (this work). Table 3 reveals that when using the Hund's case (c) expressions in the fit, the B values yielded for theà 2 P 1=2 andà 2 P 3=2 states differ slightly for both BaOH and BaOD, ($0.2111 versus 0.2136 cm À1 and $0.1919 versus 0.1935 cm À1 respectively).…”

“…We recently reported the first high resolution analysis of thẽ A 2 P ÀX 2 R þ transition of BaOH [9]. It was demonstrated that the pure precession model and unique perturber approximation are not valid for theB 2 R þ andà 2 P states.…”