Quantitative spectroscopic studies of the valence-shell electronic excitation of freons (CFCl3, CF2Cl2, CF3Cl, and CF4) in the VUV and soft X-ray regions

Au, Jennifer W.; Burton, Gordon R.; Brion, C.E.

doi:10.1016/s0301-0104(97)00146-8

Cited by 55 publications

(35 citation statements)

References 56 publications

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“…Electron impact studies include measurements on electron energy loss [33][34][35][36][37][38][39][40][41], excitation [42], ionization observing total [43,44], total dissociation [45] and partial ionization cross sections using fragment ion mass analysis [42,[46][47][48][49][50][51][52]. Furthermore, binary (e, 2e) studies [53,54] and electron impact fragment ion-photon coincidences (FIPCO) [55] were performed.…”

Section: Introductionmentioning

confidence: 99%

An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

et al. 2018

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Abstract. We study ionization and fragmentation of tetrafluoromethane (CF4) molecule induced by electron impact at low energies (E0 = 38 and 67 eV). We use a reaction microscope combined with a pulsed photoemission electron beam for our experimental investigation. The momentum vectors of the two outgoing electrons (energies E1, E2) and one fragment ion are detected in triple coincidence (e, 2e + ion). After dissociation, the fragment products observed are CF3 + , CF2 + , CF + , F + and C + . For CF3 + and CF2+ channels, we measure the ionized orbitals binding energies, the kinetic energy (KE) of the charged fragments and the two-dimensional (2D) correlation map between binding energy (BE) and KE of the fragments. From the BE and KE spectra, we conclude which molecular orbitals contribute to particular fragmentation channels of CF4. We also measure the total ionization cross section for the formation of CF3 + and CF2 + ions as function of projectile energy. We compare our results with earlier experiments and calculations for electron-impact and photoionization. The major contribution to CF3 + formation originates from ionization of the 4t2 orbital while CF2+ is mainly formed after 3t2 orbital ionization. We also observe a weak contribution of the (4a1) −1 state for the channel CF3 + .

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Section: Introductionmentioning

confidence: 99%

An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

et al. 2018

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“…The polyhalogenated derivatives of methane have abundantly been studied in the last fifteen years [18][19][20][21] using almost all available spectroscopic techniques. The monosubstituted species received much less attention, and among them particularly CH 3 Br.…”

Section: Introductionmentioning

confidence: 99%

The vacuum UV photoabsorption spectrum of methyl bromide (CH3Br) and its perdeuterated isotopomer CD3Br: a Rydberg series analysis

et al. 2005

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The vacuum UV photoabsorption spectrum of CH 3 Br has been recorded between 6 and 25 eV. A large number of vibronic bands are observed. They were partly ascribed to vibrationless Rydberg transitions. In the high photon energy range of 12-25 eV, very weak diffuse bands are mostly assigned to transitions from the 3a 1 , le and (2a 1 + la 1 ) to 3s orbitals. In the 6-12 eV photon energy range, numerous weak to strong bands are observed. The sharpness is very variable over the entire spectral region. In a first step, the interpretation of the spectrum and the assignment of the Rydberg transitions is based on the simple Rydberg formula. The observed features are classified in two groups of four series, each converging to one of the two spin-orbit components of the X 2 E state of CH 3 Br + . Rydberg series of nsa 1 , npa 1 , npe, nd and possibly nf characters are observed. The same measurements have been made for the first time on CD 3 Br in the 6-12 eV photon energy range. The observed features are classified into the same Rydberg series characterized by nearly the same δ values. Ionization energies for CD 3 Br X 2 E 3/2 at 10.565 eV and X 2 E 1/2 at 10.902 eV are deduced. In a second step, we fitted the experimental data to an energy expression taking into account both the exchange interaction and the spin-orbit coupling. Already states with n = 6 are found to correspond to Hund's case (c). Constant values of the quantum defects are deduced.

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“…The halogen substituted derivatives of methane have been thoroughly studied in the last fifteen years [8,9] using most of the available spectro-scopic techniques. The monosubstituted species received much less attention, excepting mono-chloromethane CH 3 Cl.…”

Section: Introductionmentioning

confidence: 99%

The vacuum UV photoabsorption spectrum of methyl chloride (CH3Cl) and its perdeuterated isotopomer CD3Cl I. A Rydberg series analysis

et al. 2001

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The vacuum UV photoabsorption spectrum of CH 3 Cl has been recorded between 6 and 25 eV. A large number of vibronic bands are observed. These were partly ascribed to vibrationless Rydberg transitions. In the high photon energy range of 12-25 eV, very weak diffuse bands are mostly assigned to transitions from the 3a 1 , 1e and 2a 1 to 3s orbitals. In the 6-12 eV photon energy range, numerous weak to strong bands are observed. The sharpness is very variable over the entire spectral region. In a first step, the interpretation of the spectrum and the assignment of the Rydberg transitions is based on the simple Rydberg formula. The observed features are classified in two groups of four series, each converging to one of the two spin-orbit components of the X 2 E state of CH 3 Cl + . Rydberg series of nsa 1 (δ = 1.069 and 1.064), npa 1 (δ = 0.68 and 0.66), npe (δ = 0.438 and 0.427) and nd (δ = -0.040 and -0.092) characters are observed. The same measurements have been made for the first time on CD 3 C1 in the 6-12 eV photon energy range. The same Rydberg transitions are observed. Analogous series are characterized by about the same δ values: nsa 1 (δ = 1.038 and 0.968), npa 1 (δ = 0.65 and 0.61), npe (δ = 0.458 and 0.462) and nd (δ = -0.004 and -0.082). Ionization energies for CD 3 Cl X 2 E 3/2 at 11.320 eV and X 2 E 1/2 at 11.346 eV are deduced. In a second step, we fitted the experimental data for the nsa 1 and npa 1 states to an energy expression taking into account both the exchange interaction and the spin-orbit coupling. This accounts for the progressive switching from Hund's case (a) to Hund's case (c).

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Quantitative spectroscopic studies of the valence-shell electronic excitation of freons (CFCl3, CF2Cl2, CF3Cl, and CF4) in the VUV and soft X-ray regions

Cited by 55 publications

References 56 publications

An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

An (e, 2e+ ion) study of electron-impact ionization and fragmentation of tetrafluoromethane at low energies

The vacuum UV photoabsorption spectrum of methyl bromide (CH3Br) and its perdeuterated isotopomer CD3Br: a Rydberg series analysis

The vacuum UV photoabsorption spectrum of methyl chloride (CH3Cl) and its perdeuterated isotopomer CD3Cl I. A Rydberg series analysis

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