Quantum beats in single rovibronic state fluorescence of biacetyl

Collisional depolarization of OH(A) studied by Zeeman quantum beat spectroscopy

“…However, the signal-to-noise ratios they obtained were relatively low, and it was only with the use of pulsed tunable dye laser radiation [5] that QBS started to find numerous applications. Since then, quantum beats have been observed in diatomics [6], triatomics [7], stable [8,9] and unstable polyatomics [10,11], as well as in condensed matter, for example, in semiconductors [12]. QBS has been employed to determine structural properties such as the electric dipole moment of the electronically excited state [13] (and more recently of excited vibrational levels of the ground electronic state [14]), hyperfine constants [15], spin-orbit matrix elements and asymmetry-splittings (see [16] and references therein), and quantities relevant to both intramolecular [17,18] and intermolecular dynamical processes [19,20].…”

Electronic spectra of molecules with two C3v internal rotors: Torsional analysis of the LIF spectrum of biacetyl

“…Although the spectrum was recorded by many research groups, the assignment of these torsional bands has not been straightforward. Jet-cooled LIF spectra were studied by Campargue and Soep [1], Chaiken et al [2], Gurnick et al [3], and Kamei et al [4], all of whom assigned the lowest energy band observed in these cold jet spectra, at 22 336 cm À1 , as theà 1 A u -X 1 A g band origin. However, Saenger et al [5] observed three bands to the red of 22 336 cm À1 under warm and cold jet conditions, and suggested reassigning the band origin to 22 182 cm À1 .…”

Rotationally resolved laser-induced fluorescence of biacetyl in A 1Au–X 1Ag

“…1,2 Most of the transitions of biacetyl between the electronic ground state X 1 A g and the first singlet excited state A 1 A u show quantum beat intensity modulation in fluorescence decay due to the strong interaction between the singlet and triplet states. Though the spectroscopy has been studied intensively since two decades ago, 1-10 many questions still remain, mainly because the relatively large number of atoms and the high density of states in biacetyl makes the spectrum congested.…”

“…The experiment of van der Werf and Kommandeur 4 showed that the zeropressure luminescence is composed of a fast fluorescence and a slow phosphorescence, and the luminescence was attributed to the decay of a mixed state with both singlet (A 1 A u ) and triplet (a 3 A u ) character. Jet-cooled laserinduced fluorescence excitation spectra, LIF, of A 1 A u (S 1 ) -X 1 A g (S 0 ) were studied extensively by Campargue and Soep, 5 and Chaiken et al 1,2 Their cold spectra showed a remarkable simplification with respect to the room temperature spectra. The lowest-energy band that was ob-served in the cold jet spectrum at 22 336 cm Ϫ1 was assigned to be the band origin of the A 1 A u -X 1 A g transition.…”