Subpicosecond transient absorption study of the UV two-photon excitation of liquid alkanes

Sander, M.; Brummund, Uwe; Luther, K.; Troe, J.

doi:10.1021/j100134a003

Cited by 48 publications

(41 citation statements)

References 5 publications

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“…Rather than the kinetics, as observed by transient absorption measurements, being controlled by the classical diffusion of the electron-cation pair, it was proposed that the observed kinetics are due to a fragmentation of higher excited singlet states. 16 In this paper we discuss the reasons that we believe this interpretation to be incorrect and present data on both the linear and the branched alkanes, which exhibit different kinetics, and which together further support our original interpretation of the experimental data in terms of an Onsager recombination process.…”

mentioning

confidence: 58%

Femtosecond transient absorption studies of electrons in liquid alkanes

Long¹,

Lu²,

Eisenthal³

1995

J. Phys. Chem.

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mentioning

confidence: 58%

Femtosecond transient absorption studies of electrons in liquid alkanes

Long¹,

Lu²,

Eisenthal³

1995

J. Phys. Chem.

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“…Most researchers have focused on electron dynamics in water, [1][2][3][4][5] but studies have also been carried out in alcohols, [6][7][8] and a few nonhydroxylic solvents. [9][10][11] Here we report an investigation into the excess electron in acetonitrile (CH 3 CN). Like water, acetonitrile is highly polar and has a subpicosecond solvation response time, making it an interesting medium for dynamical studies of excess electron solvation.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond electron ejection in liquid acetonitrile: Evidence for cavity electrons and solvent anions

Xia

Peón

Kohler

2002

The Journal of Chemical Physics

138

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Articles you may be interested inPhotodetachment and electron reactivity in 1-methyl-1-butyl-pyrrolidinium bis(trifluoromethylsulfonyl)amide J. Chem. Phys. 137, 034512 (2012); 10.1063/1.4736569Collisional electron transfer to photoexcited acceptor radical anions Two-photon dissociation and ionization of liquid water studied by femtosecond transient absorption spectroscopyExcess electrons were studied in liquid acetonitrile at room temperature by femtosecond pumpprobe spectroscopy. Using Ϸ200 fs, 265 nm laser pulses, electrons were ejected into the liquid by photodetachment from iodide ions and, in separate experiments, by photoionization of indole. A strong and broad absorption band with a maximum near 1400 nm was observed in both systems. A second absorption band was observed at wavelengths below 620 nm for iodide solutions, but was not seen in photoexcited indole due to overlapping excited state absorption. The bands are in good agreement with ones seen previously in nanosecond pulse radiolysis experiments ͓I. P. Bell, M. A. J. Rodgers, and H. D. Burrows, J. Chem. Soc., Faraday Trans. 1 73, 315 ͑1977͔͒. Bell, Rodgers, and Burrows assigned the visible and IR bands to absorption by acetonitrile dimer and monomer anions, respectively. Our results strongly question this interpretation. Instead, we assign the short-wavelength absorption band to a solvent-bound valence anion consisting of one or two acetonitrile molecules and the IR band to a solvated or cavity electron. Low-level quantum chemical calculations indicate that valence anion formation is strongly correlated with CCN bending, but do not provide a clear indication of whether a monomer or dimer valence anion is favored. The highly mobile cavity electron is scavenged by added chloroform at a bimolecular reaction rate of (1.02 Ϯ0.03)ϫ10 11 M Ϫ1 s Ϫ1 . The appearance of both absorption bands within our time resolution suggests that the two forms of the excess electron are produced by prompt reaction with the iodide charge-transfer-to-solvent ͑CTTS͒ excited state. In support of this mechanism, strong static scavenging by chloroform was observed at both visible and IR wavelengths. For iodide in acetonitrile, the signal in the IR decays biexponentially due to competition between geminate recombination of the cavity electron with the parent iodine atom and its reaction with the solvent. Geminate recombination between the solvated electron and the parent iodine atom occurs with a characteristic time constant of Ϸ30 ps, while additional solvent anions are formed in a slow reaction with a time constant of Ϸ260 ps. Approximately 30% of the solvated electrons photodetached from iodide undergo geminate recombination. There is no evidence for geminate reaction between the promptly formed solvent anion and iodine, suggesting that these species are formed at larger initial separation than the IR-absorbing cavity electron/iodine atom pair. In indole, geminate recombination occurs on a slower time scale of Ϸ135 ps.

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“…1,2 More recently, a long series of experimental studies has been devoted to the investigations of the structural and dynamical properties of excess electrons in various solvents. [3][4][5][6][7][8][9][10][11][12] Quantitative theoretical investigations into the solvated electron problem became feasible after the development of powerful computers and efficient numerical program packages to solve the Schrödinger equation for the given problem. Among the theoretical methods, recently developed quantum-classical molecular dynamics techniques [13][14][15] were successfully employed for the detailed characterization of various features of an excess electron in water and methanol baths.…”

Section: Introductionmentioning

confidence: 99%

A quantum chemical study of negatively charged methanol clusters

Túri

1999

The Journal of Chemical Physics

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We performed high-level quantum chemical density functional theory calculations on negatively charged methanol clusters containing up to six monomers. The calculations suggest that there exist stable methanol cluster anions and that these anions are more stable than similar cluster anions of water. Linear hydrogen bonded methanol chains are observed to bind the excess electron on dipole bound states. The orientation and the size of the excess electron were characterized by the position of the center of mass and the radius of gyration of the highest occupied molecular orbital ͑HOMO͒. The electron occupies a large diffuse orbital concentrated outside the molecular frame in the molecular dipole direction. The tendencies of the dipole moments, the vertical electron detachment energies, and the size of the HOMOs all fit in the same cooperative trend, suggesting stronger interactions in larger anions. We also located stable cluster anions which can serve as model systems for the solvated electron in liquid methanol. Multiple O-H¯e Ϫ interactions with dominantly bond-oriented arrangement toward the solvated electron are probably strongly favored in the liquid phase for energetic reasons. Although the size of the excess electron is still significantly larger than expected from quantum molecular dynamics simulations, the general decreasing trend of the radius of gyration with increasing cluster size is reassuring. Similarly to the O-H¯e Ϫ interactions, we located C-H¯e Ϫ interactions between appropriately oriented methyl hydrogens and the excess electron in a large anion of six methanol molecules. We propose the interactions of both the hydroxyl hydrogens and the methyl hydrogens with the excess electron to be considered hydrogen bonds.

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Subpicosecond transient absorption study of the UV two-photon excitation of liquid alkanes

Cited by 48 publications

References 5 publications

Femtosecond transient absorption studies of electrons in liquid alkanes

Femtosecond transient absorption studies of electrons in liquid alkanes

Femtosecond electron ejection in liquid acetonitrile: Evidence for cavity electrons and solvent anions

A quantum chemical study of negatively charged methanol clusters

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