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>Fluorescence excitation spectra, lifetimes, and quenching of S2(Bthinsp;3Sgr;uminus;) in the wavelength region 280ndash;315 nm
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Fluorescence excitation spectra, lifetimes, and quenching of S2(Bthinsp;3Sgr;uminus;) in the wavelength region 280ndash;315 nm
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机译：Fluorescence excitation spectra, lifetimes, and quenching of S2(Bthinsp;3Sgr;uminus;) in the wavelength region 280ndash;315 nm
Fluorescence lifetimes have been determined for S2vapor excited to theBthinsp;3Sgr;uminus;state at wavelengths in the range 280ndash;315 nm, with a spectral resolution of sim;0.5 cmminus;1. For states withvprime;les;8, excitation in the bandhead region leads to fluorescence lifetimes of sim;30ndash;45 ns. In addition, lowhyphen;intensity peaks with much longer lifetimes are observed throughout the absorption spectrum. The decreased intensity and increased lifetime are attributed to perturbations by theBprime;thinsp;3pgr;ustate. For thevprime;= 9 state, lifetimes generally decrease as the excitation wavelength moves away from the bandhead and at some wavelengths a double exponential decay was observed. Although thevprime;= 10 state is known to predissociate, weak fluorescence peaks with very short lifetimes (3 ns) were observed. The addition of Ar as a quenching gas leads to complex fluorescence decay curves with two or three components for bothvprime;= 3 andvprime;= 9 states. Lifetimes and quenching rate constants obtained in this work agree with those measured previously in this laboratory using a broadhyphen;band excitation source.
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