A study of the CF radical with PE and CIS spectroscopy: investigation of Rydberg states above the first ionization threshold

Innocenti, Fabrizio; Zuin, Lucia; Costa, M.L.; Dias, Ângela; Goubet, Manuel; Morris, Alan; Oleriu, R. I.; Stranges, Stefano; Dyke, John M.

doi:10.1080/00268970601075279

Cited by 9 publications

(4 citation statements)

References 24 publications

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“…1 This is part of an ongoing research project to study the photoionization behavior of reactive atoms and molecules with synchrotron radiation. [2][3][4][5][6] This work on S atoms is both of fundamental importance and relevant to the properties of the solar atmosphere. The fundamental interest in S atoms arises from a need to understand the photoionization behavior of reactive open shell atoms, 7 a topic that we have already contributed to with angularly resolved PES and CIS studies on O and N atoms with synchrotron radiation.…”

Section: Introductionmentioning

confidence: 99%

Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0–30.0eV using constant-ionic-state spectroscopy

Innocenti

Zuin

Costa

et al. 2007

The Journal of Chemical Physics

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The partial photoionization cross sections and asymmetry parameters of S atoms have been measured using constant-ionic-state ͑CIS͒ spectroscopy in the photon energy range 10.0-30.0 eV. The ionizations investigated in these CIS experiments are the ͑3p͒ −1 ionizations S + ͑ 4 S͒ ← S͑ 3 P͒, S + ͑ 2 D͒ ← S͑ 3 P͒, and S + ͑ 2 P͒ ← S͑ 3 P͒. For the first time Rydberg series which converge to the fourth ionization limit have been observed and assignments of these series have been proposed. These correspond to excitations to Rydberg states that are parts of series which converge to the fourth ionization limit, S + ͑ 4 P͒ ← S͑ 3 P͒ ͑3s͒ −1 , and autoionize to the lower S + ͑ 4 S͒, S + ͑ 2 D͒, or S + ͑ 2 P͒ states. For each series observed in the CIS spectra photoelectron angular distribution studies, combined with other evidence, has allowed the angular momentum character of the free electron on autoionization to be determined.

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Section: Introductionmentioning

confidence: 99%

Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0–30.0eV using constant-ionic-state spectroscopy

Innocenti

Zuin

Costa

et al. 2007

The Journal of Chemical Physics

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“…In the present case, a set of molecules with CF bonds was chosen for which the observed vibrational frequencies agree with those calculated by DFT (taking into account anharmonic corrections). Figure plots a data set that ranges from fluoromethane to diatomic CF + (the ground-state singlet of which exhibits an experimental harmonic component of 1793 cm −1 versus a calculated value of 1783 cm −1 ). For example, the 12 fundamentals that were calculated for fluoroethylene at B3LYP/6-31G** (with anharmonic corrections) differ from the reported experimental frequencies by 0.6%, on average .…”

Section: Resultsmentioning

confidence: 99%

Structure, Vibrational Spectra, and Unimolecular Dissociation of Gaseous 1-Fluoro-1-phenethyl Cations

2008

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The multiple CF bond character of PhCFMe (+) ions has been examined by means of theory, vibrational spectroscopy of the gaseous ions, and unimolecular decomposition chemistry. Atoms in Molecules analysis of DFT wave functions gives a CF bond order of n = 1.25 (as compared with n = 1.38 for Me 2CF (+), relative to n = 1 for fluoromethane and n = 2 for diatomic CF (+)), which is consistent with calculations of adiabatic CF stretching frequencies (nu CF). Experimental gas phase IR spectra, recorded by means of resonant multiphoton dissociation (IRMPD) using a free-electron laser connected to an FTICR mass spectrometer, show good agreement with predicted band positions for five deuterated isotopomers of PhCFMe (+). Metastable ion decompositions of deuterated analogues of PhCFMe (+) show the same HF/DF loss patterns as those produced by IRMPD. The evidence supports the conclusion that PhCFMe ions retain structural integrity until they become sufficiently excited to dissociate, whereupon they undergo intramolecular hydrogen scrambling that is competitive with HF/DF expulsion. Relative rates of hydrogen transposition and unimolecular dissociation are extracted from relative experimental fragment ion abundances. The predominant decomposition pathway is inferred to operate via a five-center transition state, as opposed to a four-center transition state for HF loss from gaseous Me 2CF (+).

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“…The experiments reported here were undertaken on the circularly polarized beamline (4.2R, Polar) at the Elettra synchrotron radiation source using a PE spectrometer which has been specifically designed to study reactive intermediates with synchrotron radiation [17][18][19]. In addition to the TPE measurements, PE spectra were recorded as described in earlier work [19,20] and the same procedures used in these studies were used to normalize the spectra for photon flux and the transmission function of the spectrometer.…”

Section: Methodsmentioning

confidence: 99%

Threshold photoelectron spectroscopy of vibrationally excited nitrogen

Innocenti

Eypper

Stranges

et al. 2013

J. Phys. B: At. Mol. Opt. Phys.

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Threshold photoelectron spectroscopy (TPES) has been used to study flowing nitrogen subjected to a microwave discharge. The first three photoelectron (PE) bands of nitrogen corresponding to the ionizations N2+ (X2Σ+g) v+ ← N2 (X1Σ+g) v″, N2+ (A2Πu) v+ ← N2 (X1Σ+g) v″ and N2 + (B2Σ+u) v+ ← N2 (X1Σ+g) v″ were investigated. An analysis of the vibrationally resolved threshold photoelectron (TPE) spectra shows evidence of population of the vibrational levels v″ = 0–5 in the N2 X1Σ+g neutral state. By a comparison with the PE spectrum recorded under the same conditions, use of computed Franck–Condon factors for each ionization and evidence from vacuum ultraviolet absorption spectroscopy, the relative intensities of vibrational components in a TPE band can be qualitatively explained using the Franck–Condon factors for each ionization as well as the gain in intensity from autoionization from Rydberg states that are degenerate with an ionization threshold or lie just above a threshold. The enhancement in intensity obtained in the TPE spectra, relative to the intensity in a PE spectrum recorded under the same conditions, was estimated as at least one order of magnitude. The first band of atomic nitrogen was also observed in the discharge-on TPE spectra. The experimental resolution was sufficiently good to allow the three ionizations N+(3P0,1,2) ← N(4S3/2) to be resolved and their relative component intensities were measured as 1: 0.95 ± 0.10: 0.70 ± 0.10. The complementary nature of the TPES and PES techniques has been outlined and the extra information obtained from studying a vibrationally excited small molecule such as N2 with these methods has been demonstrated.

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A study of the CF radical with PE and CIS spectroscopy: investigation of Rydberg states above the first ionization threshold

Cited by 9 publications

References 24 publications

Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0–30.0eV using constant-ionic-state spectroscopy

Measurement of the partial photoionization cross sections and asymmetry parameters of S atoms in the photon energy range 10.0–30.0eV using constant-ionic-state spectroscopy

Structure, Vibrational Spectra, and Unimolecular Dissociation of Gaseous 1-Fluoro-1-phenethyl Cations

Threshold photoelectron spectroscopy of vibrationally excited nitrogen

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