An electron-impact investigation of the singlet → triplet transitions in the chloro-substituted ethylenes

Koerting, C. F.; Walzl, K. N.; Kuppermann, Aron

doi:10.1016/0009-2614(84)85578-5

Cited by 22 publications

(15 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, Koerting et al's [12] EELS studies showed the vertical (C=C) *(C=C) transition to occur at 6.21 eV. The * The most recent theoretical and experimental vertical energies for the C 2 Cl 4 * triplet transition follow this trend [12,16]. However the measurements and calculations reported previously by Moore [30] and Kato et al [13] do not.…”

Section: Valence Excitation Of C 2 Clmentioning

confidence: 57%

“…Following Dauber and Brith's [11] analysis, the present local absorption maximum at 6.202 eV is tentatively attributed to the (C=C) *(C=C) transition combined with 2v 1 excitation. Similarly, Koerting et al's [12] EELS studies showed the vertical (C=C) *(C=C) transition to occur at 6.21 eV. The * The most recent theoretical and experimental vertical energies for the C 2 Cl 4 * triplet transition follow this trend [12,16].…”

Section: Valence Excitation Of C 2 Clmentioning

confidence: 87%

“…In addition, Koerting et al [12] have carried out electron scattering experiments probing its singlet and triplet excited states, while semi-empirical self-consistent field molecular orbital (SCF MO) calculations have been performed by Kato et al [13]. The molecule's multi-photon ionization spectroscopy has been studied in detail by Williams and co-workers [14,15].…”

Section: Introductionmentioning

confidence: 99%

“…Moore [30] observed a local maximum at 4.2 eV for He + energy loss following 3 keV impact upon C 2 Cl 4 . The only EELS data available in the literature shows a band extending from 2.6 to 4.5 eV with maximum at 3.54 eV [12]. The high-energy limit of this EELS structure is consistent with the present photoabsorption feature, while the energy of the band maximum agrees with the most recently calculated value of 3.53 eV for electronic promotion from the HOMO to a *(C=C) orbital (excitation to the 1 The shoulder centered at 5.90 eV is attributed to a (C=C) *(C=C) singlet transition in agreement with Dauber and Brith [11] and Robin [19].…”

mentioning

confidence: 99%

See 3 more Smart Citations

Electronic state spectroscopy of C2Cl4

et al. 2009

View full text Add to dashboard Cite

The VUV spectrum of C 2 Cl 4 is reported in the energy range 3. 8-10.8 eV (325-115 nm). Several photoabsorption features are observed for the first time, including a very weak low-lying band which is provisionally attributed to a * triplet transition. Recent ab initio calculations of the molecule's electronic transitions [Arulmozhiraja et al. J. Chem. Phys. 129 (2008) 174506] provide the basis for the present assignments below 8.5 eV. An extended nd series is proposed to account for several higher-energy Rydberg bands. The identification of vibrational structure, dominated by symmetric C=C and CCl 2 stretching in excitations from the HOMO, largely agrees with previous spectroscopic studies. The present absolute photoabsorption cross sections cover a wider energy range than the previous measurements and are used to calculate UV photolysis lifetimes of this aeronomic molecule at altitudes between 20 and 50 km. Key Words ACCEPTED MANUSCRIPT IntroductionAs a halogenated atmospheric gas with no known natural sources, tetrachloroethylene (C 2 Cl 4 ) has been the subject of various studies focusing on the environmental effects of industrial emissions [1][2][3][4]. In particular, the compound is used extensively as a dry-cleaning solvent and a degreasing agent. Indeed its dispersion has been studied as a tracer for urban/industrial activities [5]. The UV photoabsorption spectrum and absolute cross sections can be used to monitor the concentration of C 2 Cl 4 molecules in various industrial and atmospheric contexts, while its electronic state spectroscopy provides key insights into photo-induced dissociation with applications in modeling gas-phase chemistries. Accordingly, the present absolute cross sections for the broad absorption band dominated by the dissociative (C=C) *(C=C) transition have been used to calculate solar UV photolysis rates at altitudes from 20 to 50 km (section 4.3). As a source of Cl and CCl 2 radicals, stratospheric C 2 Cl 4 can contribute to ozone depletion. Indeed Kindler et al. [1] have reported an ozone depletion potential (ODP, relative to CF 3 Cl) for C 2 Cl 4 of ~6×10 -3 , similar to the more abundant CH 3 Cl.UV photoabsorption by C 2 Cl 4 has been studied on several previous occasions [6][7][8][9][10][11]. In addition, Koerting et al. [12] have carried out electron scattering experiments probing its singlet and triplet excited states, while semi-empirical self-consistent field molecular orbital (SCF MO) calculations have been performed by Kato et al. [13]. The molecule's multi-photon ionization spectroscopy has been studied in detail by Williams and co-workers [14,15]. However, prior to Arulmozhiraja et al. 's [16] recent work, no ab initio calculations of the single-photon absorption electronic transitions (energies and oscillator strengths) were available to support the UV spectral assignments. In the present work, it has therefore been possible to draw upon advanced theoretical calculations for the first time in order to interpret the electronic state spectroscopy of C 2 ...

show abstract

Section: Valence Excitation Of C 2 Clmentioning

confidence: 57%

Section: Valence Excitation Of C 2 Clmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Electronic state spectroscopy of C2Cl4

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Multi-photon ionisation spectra for tetrachloroethene have been published by Heath and Robins and Duttont et al [12,13]. The photoabsorption spectrum of trichloroethene has been studied by Walsh and Warsop [14], and the electron energy loss spectra of both molecules has been published by Koerting et al [15]. Electron ionisation cross sections have also been reported for both tri-and tetrachloroethene from threshold to 200 eV [16].…”

Section: Introductionmentioning

confidence: 92%

Threshold photoelectron photoion coincidence spectroscopy of trichloroethene and tetrachloroethene

et al. 2008

View full text Add to dashboard Cite

The threshold photoelectron, the threshold photoelectron photoion coincidence and ion breakdown spectra of trichloroethene and tetrachloroethene have been recorded from 9 -22 eV. Comparisons with the equivalent data for the three dichloroethene molecules and theoretical calculations highlight the nature of the orbitals involved during photoionisation in this energy range. The ground electronic state of C 2 HCl 3 + (C 2 Cl 4 + ) is bound, with excited valence states dissociating to C 2 HCl 2 + (C 2 Cl 3 + ) and C 2 HCl + (C 2 Cl 2 + ). Appearance energies suggest that C 2 HCl + forms from C 2 HCl 3 + by loss of two chlorine atoms, whereas C 2 Cl 2 + forms from C 2 Cl 4 + by loss of a Cl 2 molecule. The translational kinetic energy release into C 2 HCl 2 + (C 2 Cl 3 + ) + Cl is determined as a function of energy. In both cases, the fraction of the available energy released into translational energy of the two products decreases as the photon energy increases.3

show abstract