Rotational analysis of some vibronic bands in the 3A
 u←1A
 g transition of glyoxal. Spin splittings in the lowest triplet state of the isolated molecule

Spangler, Lee H.; Pratt, David W.; Birss, F. W.

doi:10.1063/1.450992

Cited by 32 publications

(28 citation statements)

References 29 publications

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“…Note that all three coupling routes bring transition moments to the Iz> state with in-plane polarization. This is consistent with the photoselection results by Kelder et al [29] and the most recent supersonic jet data of Pratt et al [30]. The existence of low-lying 3B 9 states, and their prominence in inducing phosphorescence, must be considered a unique structural feature of the a-dicarbonyls.…”

Section: A-dicarbonylssupporting

confidence: 82%

Magnetic resonance studies of triplet carbonyls

Chan

1987

Reviews of Chemical Intermediates

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Section: A-dicarbonylssupporting

confidence: 82%

Magnetic resonance studies of triplet carbonyls

Chan

1987

Reviews of Chemical Intermediates

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“…These low K a sub-band positions are dependent on the spin-rotation constants a and a 0 . 22,35 By altering the spinrotation constants, it is possible to bring the simulations in Fig. 7 into agreement with the observed spectrum in FIG.…”

Section: Computational Resultsmentioning

confidence: 61%

“…For polyatomic molecules such as acrolein, the modeling of singlet-triplet rotational structure also requires 35 the inclusion of spin-spin constants (α and β) and spin-rotation constants (a and a 0 ) for the triplet state. To obtain estimates for these parameters, we relied on previous spectroscopic results on 2-cyclopenten-1-one.…”

Section: B Analysis Of Room-temperature 0 0 0 Band Rotational Contourmentioning

confidence: 99%

Lowest triplet (n, π*) electronic state of acrolein: Determination of structural parameters by cavity ringdown spectroscopy and quantum-chemical methods

Hlavacek

McAnally

Drucker

2013

The Journal of Chemical Physics

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The cavity ringdown absorption spectrum of acrolein (propenal, CH(2)=CH-CH=O) was recorded near 412 nm, under bulk-gas conditions at room temperature and in a free-jet expansion. The measured spectral region includes the 0(0)(0) band of the T(1)(n, π*) ← S(0) system. We analyzed the 0(0)(0) rotational contour by using the STROTA computer program [R. H. Judge et al., J. Chem. Phys. 103, 5343 (1995)], which incorporates an asymmetric rotor Hamiltonian for simulating and fitting singlet-triplet spectra. We used the program to fit T(1)(n, π*) inertial constants to the room-temperature contour. The determined values (cm(-1)), with 2σ confidence intervals, are A = 1.662 ± 0.003, B = 0.1485 ± 0.0006, C = 0.1363 ± 0.0004. Linewidth analysis of the jet-cooled spectrum yielded a value of 14 ± 2 ps for the lifetime of isolated acrolein molecules in the T(1)(n, π*), v = 0 state. We discuss the observed lifetime in the context of previous computational work on acrolein photochemistry. The spectroscopically derived inertial constants for the T(1)(n, π*) state were used to benchmark a variety of computational methods. One focus was on complete active space methods, such as complete active space self-consistent field (CASSCF) and second-order perturbation theory with a CASSCF reference function (CASPT2), which are applicable to excited states. We also examined the equation-of-motion coupled-cluster and time-dependent density function theory excited-state methods, and finally unrestricted ground-state techniques, including unrestricted density functional theory and unrestricted coupled-cluster theory with single and double and perturbative triple excitations. For each of the above methods, we or others [O. S. Bokareva et al., Int. J. Quantum Chem. 108, 2719 (2008)] used a triple zeta-quality basis set to optimize the T(1)(n, π*) geometry of acrolein. We find that the multiconfigurational methods provide the best agreement with fitted inertial constants, while the economical unrestricted Perdew-Burke-Ernzerhof exchange-correlation hybrid functional (UPBE0) technique performs nearly as well.

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“…3 The transition energy of the T 1 r S 0 0 0 0 band is observed to be almost the same as that in a neat polycrystal at 4.2 K, 18 which is appreciably larger than that in glyoxal. This increase of the transition energy can be interpreted by considering the large electronegativity of the Cl atom, which stabilizes the n -(a g ) orbital with a larger shift than the π* 3 (a u ) orbital as discussed by Möller and Tinti.…”

Section: Resultsmentioning

confidence: 78%

Radiative and Nonradiative Processes in the Excited States of Jet-Cooled Oxalyl Chloride

et al. 1996

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Phosphorescence and fluorescence excitation spectra of oxalyl chloride (COCl) 2 have been observed in a supersonic jet. Strong phosphorescence was observed for excitation of the 0 0 0 band of the T 1 3 A u (nπ*) r S 0 transition. From a vibrational analysis, it is shown that the molecule has C 2h symmetry in the T 1 excited state as well as in the S 0 ground state. Small splittings due to 35 Cl and 37 Cl isotopes were found in several vibronic bands. For the excitation of the S 1 0 0 0 band, phosphorescence with a short lifetime was observed, indicating fast intersystem crossing in the origin level. In the higher energy region, we could not observe phosphorescence but only weak fluorescence. It suggests existence of active nonradiative processes such as internal conversion and predissociation in the vibrationally excited levels of the S 1 state. A single-vibronic-level (SVL) dispersed phosphorescence spectrum has also been observed for the excitation of the T 1 CdO stretching band. The spectrum was dominated by bands at the same wavelengths as those for the 0 0 0 excitation. This clearly shows that intramolecular vibrational redistribution (IVR) takes place within the long triplet lifetime. Although oxalyl chloride is assumed to be a "small molecule", the radiationless transitions have been found to be efficient in both the T 1 and S 1 states.

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Rotational analysis of some vibronic bands in the 3A u←1A g transition of glyoxal. Spin splittings in the lowest triplet state of the isolated molecule

Cited by 32 publications

References 29 publications

Magnetic resonance studies of triplet carbonyls

Magnetic resonance studies of triplet carbonyls

Lowest triplet (n, π*) electronic state of acrolein: Determination of structural parameters by cavity ringdown spectroscopy and quantum-chemical methods

Radiative and Nonradiative Processes in the Excited States of Jet-Cooled Oxalyl Chloride

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