Time-resolved two-color photoacoustic and multiphoton ionization spectroscopy of aniline

Moll, David; Parker, G. R. Jun.; Kuppermann, Aron

doi:10.1063/1.446501

Cited by 16 publications

(3 citation statements)

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“…Time-resolved photoacoustic and multiphoton ionization spectroscopic studies of aniline show that the energy deposited into aniline can be selectively directed either into ionization or dissociation. 83 The initial yield of the first singlet excited state in the pulse radiolysis of aniline is very low. This state is populated through the internal conversion from the higher-energy singlet excited states over a period of ∼10 ns.…”

Section: ' Results and Discussionmentioning

confidence: 99%

Role of the Low-Energy Excited States in the Radiolysis of Aromatic Liquids

2011

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The contribution of the low-energy excited states to the overall product formation in the radiolysis of simple aromatic liquids--benzene, pyridine, toluene, and aniline--has been examined by comparison of product yields obtained in UV-photolysis and in γ-radiolysis. In photolysis, these electronic excited states were selectively populated using UV-light excitation sources with various energies. Yields of molecular hydrogen and of "dimers" (biphenyl, bibenzyl, dipyridyl for benzene, toluene, pyridine, respectively, and of ammonia and diphenylamine for aniline) have been determined, since they are the most abundant radiolytic products. Negligibly small production of molecular hydrogen in the UV-photolysis of aromatic liquids with excitation to energies of 4.88, 5.41, 5.79, and 6.70 eV and the lack of a scavenger effect suggest that this product originates from short-lived high-energy singlet states. A significant reduction in "dimer" radiation-chemical yields in the presence of scavengers such as anthracene or naphthalene indicates that the triplet excited states are important precursors to these products. The results for toluene and aniline suggest that efficient dissociation from the lowest-energy excited triplet state leads to noticeable "dimer" production. For benzene and pyridine, the lowest-energy triplet excited states are not likely to fragment into radicals because of the relatively large energy gap between the excited state level and corresponding bond dissociation energy. The "dimer" formation in the radiolysis of benzene and pyridine is likely to involve short-lived high-energy triplet states.

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Section: ' Results and Discussionmentioning

confidence: 99%

Role of the Low-Energy Excited States in the Radiolysis of Aromatic Liquids

2011

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“…The TPI of organic compounds proceeds through two-step excitation from the S 0 to S 1 states and from the S 1 to S n states .…”

Section: Introductionmentioning

confidence: 99%

“…5 The TPI of organic compounds proceeds through two-step excitation from the S 0 to S 1 states and from the S 1 to S n states. 35 The photoionization probability of the TPI depends on the electronic character of the S 1 and S n states, which depends on the substituent of S and has influence on the properties of S(S 1 ) and S(S n ), and the electronic conformation of the radical cations. 36 Several groups involving our group have studied the TPI of a series of organic molecules from which an electron is removed and attached to the nearest solvent molecule.…”

Section: Introductionmentioning

confidence: 99%

Importance of Properties of the Lowest and Higher Singlet Excited States on the Resonant Two-Photon Ionization of Stilbene and Substituted Stilbenes Using Two-Color Two-Lasers

et al. 2005

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Radical cations of trans-stilbene and substituted trans-stilbenes (stilbenes and the radical cations denote Sand S(*+), respectively) were generated from the resonant two-photon ionization (TPI) in acetonitrile with irradiation of one-laser (266- or 355-nm laser) and with simultaneous irradiation of two-color two-lasers (266- and 532-nm or 355- and 532-nm lasers) with the pulse width of 5 ns each. The formation yields of S(*+), the TPI efficiency, depended on the properties of S in the lowest and higher singlet excited state (S(S(1)) and S(S(n))), generated from one-photon excitation with 266- or 355-nm laser and from two-photon excitation with simultaneous irradiation of 266- and 532-nm or 355- and 532-nm lasers, respectively. The TPI efficiency using two-color two-lasers increased compared with that using one-laser. It is confirmed that the TPI proceeds through two-step two-photon excitation with the S(0) --> S(1) --> S(n)() transition. In addition to the electronic character of S(S(0)) which depends on the substituent of S, oxidation potential, and molar absorption coefficient of the S(0) --> S(1) absorption as well-known important factors for the TPI efficiency, it is shown that properties of S(S(1)) and S(S(n)) such as lifetimes, electronic characters of S(S(1)) and S(S(n)), molar absorption coefficient of the S(1) --> S(n) absorption, and ionization rate from S(S(n)) are also important.

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