Laser spectroscopy of the and transitions of CaCCD

Laser spectroscopy of the –transitions of SrCCH and SrCCD

“…A rotationally-resolved spectrum of the e A 2 P-e X 2 R þ transition which permitted an analysis of the e A 2 P state was reported in 2005 [3]. In this Note we report on the spectrum of the e A 2 Pe X 2 R þ transition in SrCCD following on our recent investigation of the same transition in CaCCD [4]. SrCCH is a member of a group of molecules whose structure is well-modelled as a Sr + ion perturbed by a negatively-charged organic ligand [5].…”

“…The isotopically-substituted molecules SrOD [10], CaOD [11], and CaCCD [4] have also been studied. Consistencies between isotopic relationships for certain parameters have emerged, confirming their physical origin.…”

“…The SrCCD molecules were produced in a laser-ablation apparatus and were detected via laser-induced fluorescence. The experimental apparatus and conditions have been fully discussed in our paper on CaCCD [4], and except for the use of a strontium rod in place of the calcium rod all details related to the production of the molecule were identical, including the use of a 6% mixture of CD 4 in helium to produce the molecules of interest through interaction with strontium atoms ablated from the rod. Since the strontium acetylide spectra were shifted to longer wavelengths than those of calcium acetylide, UV-pumped LDS698 dye was used in the low-resolution pulsed laser system, and pyridine-1 dye was used in the high-resolution Coherent 699-29 cw dye laser to cover the 680-710 nm wavelength range.…”

“…The SrCCD data were fit to the 2 P-2 R + Hamiltonian used in our analysis of CaCCD and MgCCH spectra [4,13]. We found that a minimal set of parameters were required to achieve a fit to within experimental precision; centrifugal distortion parameters could not be statistically determined in either the upper or lower state, and only the band origin T 0 , spin-orbit splitting A, rotational constant B, and K-doubling parameter p were required to describe the e A 2 P state.…”

“…state is predissociative; our attempts to observe this transition using the same method were similarly unsuccessful. It would be of interest to directly observe the e B 2 R þ state and confirm the prediction of its position using the unique perturber model, perhaps using a direct-absorption technique like cavity ring down laser spectroscopy as we were able to do with CaCCH and CaCCD [4,14].…”