Laser-induced fluorescence and fluorescence depletion spectroscopy of SCCS−

Abstract

Articles you may be interested inThe electronic spectrum of the fluoroborane free radical. II. Analysis of laser-induced fluorescence and single vibronic level emission spectra In a discharged supersonic jet of carbon disulfide, a band system of a new species is observed by laser-induced fluorescence ͑LIF͒ spectroscopy. Rotationally resolved spectra show that the observed electronic transition is 2 ⌸ 3/2 -2 ⌸ 3/2 . Since both sulfur and carbon atoms have even numbers of electrons, it is concluded that the spectral carrier is an ionic species. Furthermore, the spectral carrier is confirmed to have two equivalent carbon atoms from the LIF spectra of the 13 C-substituted species. With a help of ab initio calculations, the carrier is identified as the linear negative ion SCCS Ϫ , where the observed electronic transition is considered to be à 2 ⌸ g -X 2 ⌸ u . A mass spectrometric measurement also gives evidence that SCCS Ϫ is produced in the discharged jet. The vibrational structure for the upper electronic state is determined by both LIF and fluorescence depletion spectroscopy. A dispersed fluorescence spectrum is also observed to determine the vibrational structure of the lower electronic state. Frequencies of the 1 ͑C-C stretching͒ and 2 ͑C-S symmetric stretching͒ vibrational modes are determined for both the electronic states, which are in good agreement with the theoretically calculated values. Fluorescence decay profiles are obtained for many vibronic levels, and the excited-state dynamics is discussed based on the determined fluorescence lifetimes and results of ab initio calculations.

Gas phase electronic spectrum of the HSCCS radical by laser-induced fluorescence spectroscopy

“…6, the CAS bond on the opposite end of the H atom is remarkably lengthened and the SCC bond angle next to the HAS bond decreases upon the electronic excitation, resulting in observations of the m 5 (symmetric CAS stretch) and m 7 (SCC bend) progressions in the e B 2 A 00 -e X 2 A 00 transition. Progressions of the symmetric CAS stretching also appear with significant intensities in the e A 2 P g -e X 2 P u spectra of SCCS À [3], indicating the fact that the observed electronic transitions of HSCCS and SCCS À are essentially the same. Fig.…”

“…The experimental setup for the measurements of LIF excitation spectra was similar to the one previously reported [1][2][3]. Only a brief description is therefore given here.…”

“…Recently, we reported LIF spectroscopy of a negatively charged species, SCCS À , by using the same experimental setup [3]. By comparing the molecular constants of the unidentified species with those of SCCS À , it is found that they are similar with each other, as summarized in Table 2.…”

“…Three of these band systems have been identified as 2 P-2 P electronic transitions of HC 4 S [1], HC 6 S [2], and SCCS À [3], on the basis of rotational constants, chemical tests, and ab initio calculations. However, a few band systems remain with the spectral carriers unidentified.…”

Degenerate and two‐color resonant four‐wave mixing of C2− in a molecular beam environment

“…[20,30] Recently, SCCS − has been measured by laser-induced fluorescence in a discharged supersonic jet. [31] In the latter work, fluorescence depletion spectroscopy -a variant of optical-optical double resonance spectroscopy -is employed in addition, to investigate spectral regions where the fluorescence quantum yield is very low due to a fast nonradiative process. In fact, apart from the detection of transitions that exhibit low fluorescence yield, double-resonant spectroscopic techniques are advantageous to disentangle complex spectra of polyatomic molecules and to increase the selectivity in regions where spectra of different species overlap.…”