Lifetimes in Excited States

Schlag, E. W.; Schneider, Siegfried; Fischer, Sighart F.

doi:10.1146/annurev.pc.22.100171.002341

Cited by 180 publications

(49 citation statements)

References 160 publications

(231 reference statements)

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“…They attributed it to an increase in population in higher vibrational levels with increasing photon energy. This view was further corroborated by Schlag et al 28 , who showed that the fluorescent lifetime decreases with increasing vibrational levels. Avouris et al 29 or Schlag et al 28 present a detailed discussion of the lifetimes of different vibronic states.…”

Section: Measurements Of Naphthalene Lifetime: Quenching Effectssupporting

confidence: 61%

PLIF imaging of naphthalene-ablation products in a Mach 5 turbulent boundary layer

Lochman

Murphree

Narayanaswamy

et al. 2010

27th AIAA Aerodynamic Measurement Technology and Ground Testing Conference

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A new technique is currently under development that uses planar laser-induced fluorescence (PLIF) imaging of sublimated naphthalene to image the transport of ablation products in a hypersonic boundary layer. The primary motivation for this work is to understand scalar transport in hypersonic boundary layers and to develop a database for validation of computational models. The naphthalene is molded into a rectangular insert that is mounted flush with the floor of a Mach 5 wind tunnel. The distribution of naphthalene in the boundary layer is imaged by using PLIF, where the laser excitation is at 266 nm and the fluorescence is collected in the range of 320 to 380 nm. To investigate the use of naphthalene PLIF as a quantitative diagnostic technique, a series of experiments is conducted to determine the linearity of the fluorescence signal with laser fluence, as well as the temperature and pressure dependencies of the signal. The naphthalene fluorescence at 297 K is determined to be linear for laser fluence that is less than about 200 J/m 2. The temperature dependence of the naphthalene fluorescence signal is found at atmospheric pressure over the temperature range of 297K to 525K. A monotonic increase in the fluorescence is observed with increasing temperature. Naphthalene fluorescence lifetime measurements were also made in pure-air and nitrogen environments at 300 K over the range 3.3 kPa to 101.3 kPa. The results in air show the expected Stern-Volmer behavior with decreasing lifetimes at increasing pressure, whereas nitrogen exhibits the opposite trend. Preliminary PLIF images of the sublimated naphthalene are acquired in a Mach 5 turbulent boundary layer. Relatively low signal-to-noise-ratio images were obtained at a stagnation temperature of 345 K, but much higher quality images were obtained at a stagnation temperature of 375 K. Our results indicate that PLIF of sublimating naphthalene may be an effective tool for studying scalar transport in hypersonic flows.

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Section: Measurements Of Naphthalene Lifetime: Quenching Effectssupporting

confidence: 61%

PLIF imaging of naphthalene-ablation products in a Mach 5 turbulent boundary layer

Lochman

Murphree

Narayanaswamy

et al. 2010

27th AIAA Aerodynamic Measurement Technology and Ground Testing Conference

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“…It is thus more likely that we would observe electronically specific rather than vibrationally specific competing processes. This is illustrated by the observation in several molecules of fluorescence from electronic states higher than the first excited singlet state (Schlag et al, 1971). However, there is no case in which fluorescence from other than a Boltzmann distribution of vibrational levels has been reported for a molecule in a condensed-phase environment at these temperatures.…”

Section: Amentioning

confidence: 99%

Excitation Spectroscopy of Retinal and Related Polyenes†

Christensen

Kohler

1974

Photochem & Photobiology

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Abstract— Fluorescence excitation spectra of all‐trans retinal and the related polyene hydrocarbons anhydrovitamin A and diphenyloctatetraene show that only retinal has a wavelength‐dependent fluorescence quantum yield. Three possibilities for the unusual quantum yield behavior of retinal are considered. We conclude that competition between a fast radiationless process (perhaps of photochemical origin) and internal conversion between 1ππ* states and a low‐lying 1nπ* state provides the best rationalization for the data now in hand.

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“…The fact that this lifetime is nearly independent of deuteration shows that the rapid decay channal that connects S 1 to S 0 does not involve C-H vibrations 3 whereas in many other aromatic hydrocarbons C-H stretching vibrations act as the most important promoting modes for IC. 33 To derive a more detailed understanding of the dynamic behavior of the low-lying electronic states of this unusual molecule it is necessary to determine accurate potential surfaces for all relevant states. Recently we reexamined the ground-state forcefield of biphenylene by comparing new matrix isolation IR measurements with the result of ab initio calculations 28 obtained from Hartree-Fock ͑HF͒ calculations and with density functional theory 34 ͑DFT͒.…”

Section: Introductionmentioning

confidence: 99%

Vertical and adiabatic electronic excitations in biphenylene: A theoretical study

Beck

Rebentisch

Hohlneicher

et al. 1997

The Journal of Chemical Physics

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Articles you may be interested inLow-lying electronic states and their nonradiative deactivation of thieno [3,4-b]pyrazine: An ab initio study J. Chem. Phys. 137, 224313 (2012); 10.1063/1.4770229 Improved virtual orbital multireference Møller-Plesset study of the ground and excited electronic states of protonated acetylene, C 2 H 3 + The low-lying singlet states of biphenylene have been studied using ab initio methods. Vertical excitation energies were calculated by multiconfigurational perturbation theory ͑CASPT2͒, starting from a complete active space self-consistent field ͑CASSCF͒ reference. The geometries of the most important low-lying excited states were individually optimized at the CASSCF level to study the difference between vertical and adiabatic excitations. Extended atomic natural orbital ͑ANO͒-type basis sets were used to calculate state energies. Geometry optimizations were done with smaller ANO-type basis sets. Excitations from the ground state to the 1 1 B 3g and 1 1 B 2u excited singlet states lead to pronounced geometry changes which alter the bond alternation pattern. The theoretical results provide a solid basis for the assignment and interpretation of experimental spectra.

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Lifetimes in Excited States

Cited by 180 publications

References 160 publications

PLIF imaging of naphthalene-ablation products in a Mach 5 turbulent boundary layer

PLIF imaging of naphthalene-ablation products in a Mach 5 turbulent boundary layer

Excitation Spectroscopy of Retinal and Related Polyenes†

Vertical and adiabatic electronic excitations in biphenylene: A theoretical study

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