Laser-induced fluorescence studies of jet-cooled S2O: Axis-switching and predissociation effects
J. Chem. Phys. 103, 67 (1995); doi:10.1063/1.469623
Issue Date: 1 July 1995
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Laser-induced fluorescence spectroscopy has been used to probe the intense
1A
–
1A
(
*
) electronic system of S2O (315–340 nm) under supersonic free-jet conditions that yield effective rotational temperatures of roughly 1 K. Least-squares analysis of high-resolution scans performed on the 2
(v=0–5) progression, where
2 corresponds to the S–S stretching mode, not only furnish refined band origins and rotational constants, but also provide evidence for an axis-switching effect in this asymmetric triatomic species. Based on the limited set of vibronic bands examined in the present study, the harmonic frequency and anharmonicity for S–S stretching motion in the
state are determined to be
2=415.2(4) cm−1 and x22=−2.10(6) cm−1, respectively. Predissociation of the
1A
potential energy surface is found to become more pronounced with increasing excitation of the
2 mode. Collision-free lifetime data, obtained either directly from time-resolved fluorescence decay profiles or indirectly from measurements of broadened spectral linewidths, permit formulation of a simple, one-dimensional tunneling model which predicts the excited state predissociation barrier to be located in the vicinity of the 26 vibrational level. These results, as well as possible candidates for the electronic manifold responsible for the predissociation process, are discussed in light of preliminary ab initio calculations. ©1995 American Institute of Physics.
–
(
*
) electronic system of S2O (315–340 nm) under supersonic free-jet conditions that yield effective rotational temperatures of roughly 1 K. Least-squares analysis of high-resolution scans performed on the 2
2 corresponds to the S–S stretching mode, not only furnish refined band origins and rotational constants, but also provide evidence for an axis-switching effect in this asymmetric triatomic species. Based on the limited set of vibronic bands examined in the present study, the harmonic frequency and anharmonicity for S–S stretching motion in the
2=415.2(4) cm−1 and x22=−2.10(6) cm−1, respectively. Predissociation of the
potential energy surface is found to become more pronounced with increasing excitation of the
2 mode. Collision-free lifetime data, obtained either directly from time-resolved fluorescence decay profiles or indirectly from measurements of broadened spectral linewidths, permit formulation of a simple, one-dimensional tunneling model which predicts the excited state predissociation barrier to be located in the vicinity of the 26 vibrational level. These results, as well as possible candidates for the electronic manifold responsible for the predissociation process, are discussed in light of preliminary ab initio calculations. ©1995 American Institute of Physics.
| History: | Received 9 January 1995; accepted 28 March 1995 |
| Permalink: |
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KEYWORDS and PACS
SULFUR OXIDES,
FLUORESCENCE SPECTROSCOPY,
JET FLOW,
VIBRATIONAL STATES,
POTENTIAL ENERGY SURFACES,
ROTATIONAL STATES,
PREDISSOCIATION,
TUNNELING,
ULTRAVIOLET SPECTRA,
LASER SPECTROSCOPY
- 33.50.Dq
Molecular properties and interactions with photons Fluorescence and phosphorescence; radiationless transitions, quenching (intersystem crossing, internal conversion) Fluorescence and phosphorescence spectra - 33.20.Lg
Molecular properties and interactions with photons Molecular spectra Ultraviolet spectra - 42.62.Fi
Optics Laser applications Laser spectroscopy - 33.70.Fd
Molecular properties and interactions with photons Intensities and shapes of molecular spectral lines and bands Absolute and relative line and band intensities - YEAR: 1995
RELATED DATABASES
PUBLICATION DATA
0021-9606 (print)
1089-7690 (online)
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