Molecular Ions in Radiation Chemistry. III. Absorption Spectra of Aromatic-Hydrocarbon Cations and Anions in Organic Glasses

Shida, Tadamasa; Hamill, William H.

doi:10.1063/1.1726645

Cited by 136 publications

(36 citation statements)

References 9 publications

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“…For homo-dimer radical ions, it is often seen that the intermolecular charge resonance interaction occurs in them, giving a symmetrical species; the charge is equally shared by the two components. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The dimer ion form is kept as a dimer ion core in some homo-molecular cluster ions, such as (benzene) n + . 13,14 However, the charge distribution of cluster ions is not predictable so easily on the basis of IE, PA, or EA.…”

Section: Introductionmentioning

confidence: 99%

IR photodissociation spectroscopy of (OCS)n+ and (OCS)n− cluster ions: Similarity and dissimilarity in the structure of CO2, OCS, and CS2 cluster ions

Inokuchi

Ebata

2015

The Journal of Chemical Physics

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Infrared photodissociation (IRPD) spectra of (OCS)n(+) and (OCS)n(-) (n = 2-6) cluster ions are measured in the 1000-2300 cm(-1) region; these clusters show strong CO stretching vibrations in this region. For (OCS)2 +) and (OCS)2(-), we utilize the messenger technique by attaching an Ar atom to measure their IR spectra. The IRPD spectrum of (OCS)2 (+)Ar shows two bands at 2095 and 2120 cm(-1). On the basis of quantum chemical calculations, these bands are assigned to a C2 isomer of (OCS)2 (+), in which an intermolecular semi-covalent bond is formed between the sulfur ends of the two OCS components by the charge resonance interaction, and the positive charge is delocalized over the dimer. The (OCS)n(+) (n = 3-6) cluster ions show a few bands assignable to "solvent" OCS molecules in the 2000-2080 cm(-1) region, in addition to the bands due to the (OCS)2(+) ion core at ∼2090 and ∼2120 cm(-1), suggesting that the dimer ion core is kept in (OCS)3-6(+). For the (OCS)n(-) cluster anions, the IRPD spectra indicate the coexistence of a few isomers with an OCS(-) or (OCS)2(-) anion core over the cluster range of n = 2-6. The (OCS)2(-)Ar anion displays two strong bands at 1674 and 1994 cm(-1). These bands can be assigned to a Cs isomer with an OCS(-) anion core. For the n = 2-4 anions, this OCS(-) anion core form is dominant. In addition to the bands of the OCS(-) core isomer, we found another band at ∼1740 cm(-1), which can be assigned to isomers having an (OCS)2(-) ion core; this dimer core has C2 symmetry and (2)A electronic state. The IRPD spectra of the n = 3-6 anions show two IR bands at ∼1660 and ∼2020 cm(-1). The intensity of the latter component relative to that of the former one becomes stronger and stronger with increasing the size from n = 2 to 4, which corresponds to the increase of "solvent" OCS molecules attached to the OCS(-) ion core, but it suddenly decreases at n = 5 and 6. These IR spectral features of the n = 5 and 6 anions are ascribed to the formation of another (OCS)2(-) ion core having C2v symmetry with (2)B2 electronic state.

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Section: Introductionmentioning

confidence: 99%

IR photodissociation spectroscopy of (OCS)n+ and (OCS)n− cluster ions: Similarity and dissimilarity in the structure of CO2, OCS, and CS2 cluster ions

Inokuchi

Ebata

2015

The Journal of Chemical Physics

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“…Quenching of the homopolymer with transstilbene ( Figure 6 ) resulted in an absorption band, centered at 500 nm, which could be assigned to the trans-stilbene cation. 8 To substantiate this assignment, a transient absorption spectrum of trans-stilbene in acetonitrile (obtained by using a 248 nm, 100 mJlcm2 excitation pulse) was collected. The spectrum recorded under these conditions resembled, apart from a slight (presumably solvatochromic) shift, that obtained through the quenching experiment.…”

Section: Resultsmentioning

confidence: 99%

Transient Ions and Triplet States in Polymers Containing Phenanthrene

Haggquist¹,

Hisada²,

Tsuchida³

et al. 1994

J. Phys. Chem.

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A series of phenanthryl and methylmethacrylate copolymers were synthesized and investigated by means of nanosecond laser kinetic spectroscopy. Laser-induced absorption changes (in the 400-500-nm spectral region) were attributed to the triplet state and to radical ions of phenanthrene, whose disappearance could not be explained by conventional homogeneous kinetics. Accordingly, a model was developed in which each transient species (X, say) was divided into two categories: mobile (X,) and napped (Xt). The observations could be interpreted in terms of a mechanism involving, apart from unimolecular decay (if any), two types of encounters: Xm -X m and X, -X,. The bimolecular rate constant for the annihilation process, X, + Xmproducts, was found to increase with rising phenanthrene content. The rate constant for the pseudounimolecular decay of the triplet also increased with loading, an effect attributed to migration of charge and electronic excitation, and quenching of the latter by doublet-state ionic species.

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“…Benzene, Benzene + Ethanol, and Aniline Solutions Benzene has been suggested to scavenge hydrogen atoms in the liquid phase (12,13,18). In solid phase solutions it has also been reported to scavenge electrons (19)(20)(21)(22) and positive charge (19,(22)(23)(24).…”

Section: ]mentioning

confidence: 99%

“…For positive ion scavenging, the equation analogous to [19] is Results from benzene, benzene + ethanol, and aniline solutions in hexane indicate that vp+ increases with an increase in pressure. The respective increases are --3-fold, 4-fold, and 2-fold on going from 1 bar to 4.6 kbars (Figs.…”

Section: Kinetics Considerationsmentioning

confidence: 99%

Effect of Pressure on the Rates of Reaction of Radiolysis Intermediates in Liquid n-Hexane

Jha¹,

Freeman²

1971

Can. J. Chem.

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The yield of hydrogen from pure hexane, G(H2) = 5.3 + 0.2 was independent of pressure in the range 1 bar to 4.6 kbars. The G values of Hz, HD, and Dz obtained from 11 mol% C6D14 in C6H14 were independent of pressure and were respectively, 4.85, 0.34, and 0.11. The electron and hydrogen atom scavenging efficiencies of carbon tetrachloride and hexadiene-1,3, and the hydrogen atom scavenging efficiency of hexene-1 were independent of pressure. The positive ion scavenging efficiencies of benzene and aniline increased with increasing pressure. The volume of activation for the hydrogen atom reaction with n-hexane is essentially the same as that for the reaction with hexene-1. The pressure dependence of the charge scavenging reactions has been interpreted in terms of the kinetics of spur processes. The treatment is consistent with the fact that the efficiency of the electron scavenging reactions is independent of pressure. The increased efficiency of positive ion reaction under pressure implies that the ratio of the diffusion coefficients of the radiolytic positive ion and electron, D + / D -, increases with increasing pressure.Le rendement en hydrogene pour I'hexane pur, G(H2) = 5.3 + 0.2, est independant de la pression dans le domaine de 1 bar a 4.6 kbar. Les valeurs G de Hz, H D et Dz obtenues a partir de 11 mole% de C6D14 dans C6H14 sont independantes de la pression et sont respectivement de4.85,0.34et 0.1 1. L'efficacitk du tetrachlorure de carbone et de I'hexadiene-1,3 pour capturer les electrons et les atomes d'hydrogene ainsi que I'efficacite de I'hexene-1 pour capturer les atomes d'hydrogene est independante de la pression. L'efficacite du benzene et de I'aniline pour capturer les ions positifs augmente en mCme temps que la pression. Le volume d'activation pour la reaction d'atomes d'hydrogene avec le n-hexane est essentiellement le mCme que pour la reaction avec I'hexene-1. La dependance de la pression sur les reactions de capture des charges est interpretee en termes de cinetique des reactions dans les grapkes. L'augmentation de I'efficacite des reactions des ions positifs, sous I'effet de la pression, implique que le rapport des coefficients de diffusion des ions positifs crees sous irradiation et des electrons, D + / D -, augmente avec la pression.

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Molecular Ions in Radiation Chemistry. III. Absorption Spectra of Aromatic-Hydrocarbon Cations and Anions in Organic Glasses

Abstract: Articles you may be interested inOn the vibronic structure of the absorption spectra of radical cations of some polycyclic aromatic hydrocarbons

Cited by 136 publications

References 9 publications

IR photodissociation spectroscopy of (OCS)n+ and (OCS)n− cluster ions: Similarity and dissimilarity in the structure of CO2, OCS, and CS2 cluster ions

IR photodissociation spectroscopy of (OCS)n+ and (OCS)n− cluster ions: Similarity and dissimilarity in the structure of CO2, OCS, and CS2 cluster ions

Transient Ions and Triplet States in Polymers Containing Phenanthrene

Effect of Pressure on the Rates of Reaction of Radiolysis Intermediates in Liquid n-Hexane

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