Pulse Radiolysis Study of the Formation of Triplet Excited States of Naphthalene, Anthracene, and Biphenyl in Cyclohexane Vapor
1969; American Institute of Physics; Volume: 51; Issue: 2 Linguagem: Inglês
10.1063/1.1672024
ISSN1520-9032
AutoresG. R. A. Johnson, Myran C. Sauer,
Tópico(s)Spectroscopy and Quantum Chemical Studies
ResumoThe first triplet excited state of naphthalene is produced in significant amounts when cyclohexane–naphthalene mixtures are pulse irradiated in the gas phase (120°C). The yield is independent of naphthalene concentration from 0.15 mole % up to at least 3.5 mole %, and can be decreased by about 95% by SF6, CCl4, C6H5CH2Cl, CH3Br, NH3, and H2O. The scavengeable part of the triplet yield is attributed to neutralization of the ion C10H8+ (which is formed by charge transfer from cyclohexane positive ion) by C10H8− which is itself formed by electron capture. The scavengers compete with naphthalene for positive ions or for electrons. The rate-constant ratios at 120°C for the reaction of the positive ions from cyclohexane with naphthalene and NH3, K(RH+ + C10H8) / k(RH+ + NH3) = 0.8 ± 0.2, and for electron capture by naphthalene and benzyl chloride, k(e− + C10H8) / k(e− + BzCl) = 3.0 ± 0.5, are obtained from competition studies. The triplet state of biphenyl observed in cyclohexane–biphenyl (0.2 mole %) is completely eliminated by SF6 (1 mole %). In cyclohexane–naphthalene–anthracene mixtures, energy transfer from triplet naphthalene to anthracene is observed.
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