References of "Hottmann, K"
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See detailThe Photoionization Dynamics of Methyl Iodide (CH3I): a joint Photoelectron and Mass Spectrometric Investigation.
Locht, Robert ULg; Dehareng, Dominique ULg; Hottmann, K. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2010), 43(10), 105101

The threshold photoelectron (TPES) and the photoionization mass spectrometric (PIMS) study of CH3I in the 8-20 eV photon energy range are presented. The interpretation and assignments are supported by ab ... [more ▼]

The threshold photoelectron (TPES) and the photoionization mass spectrometric (PIMS) study of CH3I in the 8-20 eV photon energy range are presented. The interpretation and assignments are supported by ab initio calculations. The TPES shows many new discrete features in the Jahn-Teller split ground X 2E (2A'-2A”) state of CH3I+. A new continuous band starting at about 11.7 eV is detected. These observations are essentially correlated with autoionizing transitions. This interpretation is supported by constant ion state (CIS) spectroscopy. A large enhancement of the transitions to the A 2A and B 2E ionic states is ascribed to large autoionizing contributions. Based on the present calculations, the weak to very weak bands in the 18.0 eV-23.0 eV photon energy range are mainly assigned to 2a1-1 ionization and to double excitations corresponding essentially to the 2e-2 4a11 and 3a1- 1 2e-1 4a11 configurations. The photoionization mass spectrometric study allowed us to investigate in detail the ionization and dissociation of CH3I+ leading to CH2+, CH3+, I+ and CH2I+ from the threshold up to 20 eV photon energy. The experimental data are compared to ab initio calculated dissociation energies. The threshold of appearance of CH3+, I+ and CH2I+ fragments are concentrated in the 12.2-12.7 eV photon energy range. All three exit channels are correlated with the ground state of CH3I+ via nonadiabatic transitions. All three fragment ions have to appear through predissociation of the ionic X 2E state and autoionizing dissociation from the (2E3/2)6p Rydberg state. This interpretation is strongly supported by the photoabsorption spectrum measured recently in the same photon energy range [1]. At higher energies, beside direct or predissociation of the A 2A1 and B 2E states of CH3I+, autoionization is also suggested to contribute to the fragmentation in all decay channels. [less ▲]

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See detailA Photoelectron Spectroscopic Investigation of Vinyl Fluoride (C2H3F). The HeI, Threshold and CIS Photoelectron Spectroscopy.
Locht, Robert ULg; Leyh, Bernard ULg; Dehareng, Dominique ULg et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2010), 43(1), 01510215

The threshold photoelectron spectrum (TPES) and the constant ion state (CIS) spectra of the individual ionic states of C2H3F have been recorded using synchrotron radiation. For comparison a well resolved ... [more ▼]

The threshold photoelectron spectrum (TPES) and the constant ion state (CIS) spectra of the individual ionic states of C2H3F have been recorded using synchrotron radiation. For comparison a well resolved HeI photoelectron spectrum (HeI-PES) has also been measured and analyzed in detail. The TPES has been measured between 9.5 eV and 35 eV photon energy. Numerous vibrational structures, reported for the first time, observed in the ground state and the six excited states of the cation are analyzed. Quantum chemical calculations have been performed and provide strong support to the assignments. State selected CIS spectra highlighted the major importance of autoionization for the production of almost all ionized states of C2H3F observed in this work. [less ▲]

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See detailAbout the Photoionization of Methyl Bromide (CH3Br). Photoelectron and Photoionization Mass Spectrometric Investigation.
Locht, Robert ULg; Leyh, Bernard ULg; Dehareng, Dominique ULg et al

in Chemical Physics (2006), 323

The threshold photoelectron (TPES) and the photoionization mass spectrometric (PIMS) study of CH3Br in the 8-20 eV photon energy range is presented. The interpretation and assignments are supported by ab ... [more ▼]

The threshold photoelectron (TPES) and the photoionization mass spectrometric (PIMS) study of CH3Br in the 8-20 eV photon energy range is presented. The interpretation and assignments are supported by ab initio calculations. The TPES shows several new discrete features in the Jahn-Teller split ground state X2E(2A'-2A") of CH3Br+. An additional continuous band starts at about 11.8 eV. These observations are both correlated with direct ionization and autoionizing transitions. This is supported by constant ion state (CIS) spectroscopy. A large enhancement of the transitions to the A2A and B2E states is ascribed to important autoionizing contributions. Based on the present calculations, the weak to very weak bands in the 17.5-22.0 eV photon energy range were mainly assigned to 2a1 ionization and to double excitations described essentially by the 2e-24a11 and 1e-12e-14a11 configurations. The photoionization mass spectrometric study allows us to investigate in detail the ionization and dissociation of CH3Br+ leading to CH2+, CH3+, Br+ and CH2Br+ from threshold up to 20 eV photon energy. The experimental data are compared to ab initio dissociation energies. At the onset, the CH3+ and CH2Br+ fragment ion production is correlated with the ground state of CH3Br+ and both fragment ions have to appear through dissociative autoionization from the (3a11/1e1)6s or 5s Rydberg state. This interpretation is supported by the photoabsorption spectrum measured recently in the same photon energy range. At higher energies, beside a likely direct (pre)dissociation of the A2A1 and B2E states of CH3Br+, autoionization also contributes to the fragmentation in all decay channels. Avoided crossings in a manyfold of 2A' states are likely to be involved. This is supported by ab initio calculations. For CH3+ the photoion-pair process is analyzed and detailed assignments are proposed on the basis of our latest VUV photoabsorption spectroscopic data. [less ▲]

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See detailAbout the Photoionization of Methyl Chloride. A Threshold Photoelectron Spectroscopic and Photoionization Mass Spectrometric investigation.
Locht, Robert ULg; Leyh, Bernard ULg; Hoxha, A. et al

in Chemical Physics (2001), 272

The threshold photoelectron spectroscopic (TPES) and the photoionization mass spectrometric (PIMS) study of Methyl Chloride (CH3Cl) in the 8-20 eV photon energy is presented. The interpretation and ... [more ▼]

The threshold photoelectron spectroscopic (TPES) and the photoionization mass spectrometric (PIMS) study of Methyl Chloride (CH3Cl) in the 8-20 eV photon energy is presented. The interpretation and assignments are supported by ab initio calculations. The detailed analysis of the TPES shows numerous features in the Jahn-Teller split ground X2E(2A'-2A") state of CH3Cl+ and a new continuus band peaking at 13.4 eV. These were assigned to both direct ionization and autoionizing transitions. The transitions to the A2A1 and to the B2E states undergo a large enhancement ascribed to important autoionizing contributions. Based on the present calculations, the weak to very weak signals in the 19-26 eV photon energy range were mainly assigned to 2a1-1 ionization and to double excitations described essentially by 2e-2, 4a11 and 1e-1, 2e-1, 4a11 configurations. The PIMS study allowed us to investigate in detail the ionization and dissociation of CH3Cl+ into CH2+, CH3+, CHCl+ and CH2Cl+ from threshold up to 20 eV photon energy. At the onset, the CH3+, CHCl+ and CH2Cl+ fragment ion production is correlated to the ground state of CH3Cl+ and all fragment ions have to appear through dissociative autoionization from the 2e->3p Rydberg state. This interpretation is supported by the photoabsorption spectrum (PAS) measured recently in the same photon energy range. At higher energies, beside direct dissociation of the A2A1 and B2E states of CH3Cl+ autoionization also contributes to the fragmentation in all decay channels. For CH3+ the photoion-pair process is analyzed and detailed assignments are proposed on the basis of recent PAS data. [less ▲]

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See detailThe photoabsorption and Constant Ion State Spectroscopy of Vinyl Bromide.
Hoxha, A.; Locht, Robert ULg; Leyh, Bernard ULg et al

in Chemical Physics (2000), 260

In this paper we report the photoabsorption and the constant ion state spectroscopy of vinyl bromide (C2H3Br). The photoabsorption spectrum was measured using synchrotron radiation and was investigated in ... [more ▼]

In this paper we report the photoabsorption and the constant ion state spectroscopy of vinyl bromide (C2H3Br). The photoabsorption spectrum was measured using synchrotron radiation and was investigated in detail between 5.0 and 12.0 eV photon energy revealing many previously unobserved structures. These features were analyzed in terms of valence to virtual valence transitions and Rydberg series. The examination of the three Rydberg series converging towards the first ionization threshold (2a"->ns, 2a"->np and 2a"->nd) leads to wavenumbers of 335+/-30, 690+/-30 and 1305+/-30 cm-1. The vibrational wavenumbers of the progressions belonging to Rydberg series converging towards the second ionization threshold are 485+/-30 and 1145+/-50 cm-1. Ab initio calculations helped the assignment of the valence transitions and of the observed vibrational wave numbers in the Rydberg series. Constant Ionic State spectra were recorded for vibronic states corresponding to the first and the second electronic states of the ion. Their fine structures are assigned to the autoionization of Rydberg states. The autoionization decay of these Rydberg states is analyzed qualitatively in terms of the vibrational nature of the final ionic state. [less ▲]

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See detailPhotoelectron Spectroscopy of Vinyl Bromide and Intramolecular Dynamics of the ionic B state.
Hoxha, A.; Locht, Robert ULg; Leyh, Bernard ULg et al

in Chemical Physics (2000), 256

In this paper we report the He(I) photoelectron spectrum (PES) and the threshold photoelectron spectrum (TPES) of C2H3Br. The fine structure in the first two ionic states in the He(I) spectrum is assigned ... [more ▼]

In this paper we report the He(I) photoelectron spectrum (PES) and the threshold photoelectron spectrum (TPES) of C2H3Br. The fine structure in the first two ionic states in the He(I) spectrum is assigned to progressions belonging partially to previously unobserved vibrational modes. The TPES has been measured between 9.0 and 25.0 eV, and the photon energy range of 9.8-12.0 eV has been investigated in more detail. Extensive calculations with the GAUSSIAN set of programs have been performed to help in the assignment of the observed features. Furthermore, a conical intersection between the A2A" and the B2A" states was found to take place along the C-Br stretching coordinate. Intramolecular dynamics of the B2A" state, initially prepared in the Franck-Condon region, was probed by the Fourier transform of the spectrum. The B2A" state is almost readily depleted, most probably due to a very effective internal cnversion through the conical intersection. [less ▲]

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See detailThe Spectroscopy of Ethylene and its Derivatives. C2H4 and the three C2H2FCl isomers. The CIS- and Threshold Photoelectron Spectra.
Locht, Robert ULg; Leyh, Bernard ULg; Hottmann, K. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1999)

The Cis- and threshold photoelectron spectra of C2H4 and the three isomers of C2H2FCl are measured using synchrotron radiation. A short analysis has also been reported.

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See detailA He(I) Photoelectron Spectroscopic Study of the X2A"2state of NH3+ and ND3+. A Reanalysis and evidence for the Coriolis Coupling between the Bending nu2 and nu4 Modes.
Locht, Robert ULg; Leyh, Bernard ULg; Hottmann, K. et al

in Chemical Physics (1998), 233

In the He(I) photoelectron spectrum of NH3 and its isotopomer ND3 the complete vibrational structure of the X2A"2 state of NH3+ and ND3+ is examined in detail. Three vibrational progressions are ... [more ▼]

In the He(I) photoelectron spectrum of NH3 and its isotopomer ND3 the complete vibrational structure of the X2A"2 state of NH3+ and ND3+ is examined in detail. Three vibrational progressions are identified. The well-known strongest progression, already unambiguously assigned to the nu2 out-of-plane bending mode, is observed from v=0-17 in NH3+ and v=0-20 in ND3+. For NH3+ this vibration could be characterized not only by its energy hcomega2= 0.109+/-0.001 eV (or omega2= 878+/-7 cm-1) but also by its first anharmonicity constant hcomega22x22=-(16.2+/-1.2)10-4 eV (or omega22x22=-13.0+/-1.0 cm-1). The best fit of the experimental data required the introduction of a second anharmonicity constant, i.e. hcomega22y22= -(30.7+/-4.2)x10-6 eV (or omega22y22=-0.248+/-0.034 cm-1). The earlier reported weak progression assigned to the vibrational combination nu1+nnu2 transitions has been reexamined. Suitable handling of the data leads to two possible energies for the nu1 degenerate NH stretching vibrational normal mode, i.e. hcomega1 =0.306+/-0.006 eV or 0.422+/-0.005 eV. Several arguments are brought to favour the value of hcomega1=0.422 eV (or omega1=3404 cm-1). Finally a third weak progression, reported for the first time, is assigned to nu4+nnu2 transitions where the nu4 in-plane bending mode is optically forbidden. This vibrational normal mode is characterized by an energy hcomega4=0.186+/-0.010 eV (omega4=1500+/-80 cm-1). In agreement with the theoretical predictions, this transition becomes allowed through a strong Coriolis vibro-rotational coupling between the nu4 and the nu2 vibrational normal modes. The same measurements and the isotope effect on the molecular constants are investigated in ND3+ too. [less ▲]

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See detailPhotoabsorption, He(I) and Threshold Photoelectron spectra and CIS-Spectroscopy of Vinylchloride.
Locht, Robert ULg; Leyh, Bernard ULg; Hottmann, K. et al

in Aumayr, F.; Betz, G.; Winter, H. P. (Eds.) XX. ICPEAC: Scientific Programme and Abstracts of Contributed Papers. Volume 1. (1997)

The Vacuum UV photoabsorption and Threshold Photoelectron spectra of C2H3Cl have been measured by using synchrotron radiation. Vibrationally resolved CIS-spectroscopy of the same molecule is also reported.

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See detailThe Photoionization of Methyl Iodide (CH3I). The Threshold Photoelectron and CIS Spectroscopy.
Locht, Robert ULg; Hoxha, A.; Leyh, Bernard ULg et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1997)

The vacuum UV photoabsorption spectrum of CH3I and its threshold photoelectron spectrum are reported. The region of 9.5-10.5 eV photon energy is recorded at high resolution.

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See detailThe Photoionization of Ethylene Monobromide (C2H3Br). The Threshold Photoelectron and CIS Spectroscopy.
Hoxha, A.; Locht, Robert ULg; Leyh, Bernard ULg et al

Book published by Berliner Elektronen Speicherring für Elektronen Synchrotron Strahlung m.b.H (1997)

The first results on the threshold photoelectron, CIS-spectroscopy and photoabsorption spectroscopy of C2H3Br are reported. A first analysis is presented.

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See detailThe He(I), Threshold photoelectron and Constant Ion State spectroscopy of Vinylchloride (C2H3Cl).
Locht, Robert ULg; Leyh, Bernard ULg; Hottmann, K. et al

in Chemical Physics (1997), 220

Using synchrotron radiation the threshold photoelectron (TPES) spectrum and constant ion state (CIS) spectroscopy of C2H3Cl are reported. For comparison, the He(I) photoelectron spectrum has also been ... [more ▼]

Using synchrotron radiation the threshold photoelectron (TPES) spectrum and constant ion state (CIS) spectroscopy of C2H3Cl are reported. For comparison, the He(I) photoelectron spectrum has also been measured and reexamined. The threshold photoelectron spectrum has been measured between 9.0 and 25.0 eV and the photon energy range of 9.9-12.0 eV has been investigated in detail. Many features have been identified and tentatively assigned with the help of the photoabsorption spectroscopic results. These data were compared with the well-resolved He(I) photoelectron spectrum. The fine structure observed in the two first ionic states is assigned to progressions belonging partially to previously unobserved vibration normal modes. State-selected CIS spectra have been recorded for the first vibronic states between 10.0 and 11.67 eV. They exhibit fine structure assigned to autoionization of Rydberg states. [less ▲]

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See detailThe Photoabsorption Spectrum of Vinylchloride (C2H3Cl) in the 8-12 eV Range.
Locht, Robert ULg; Leyh, Bernard ULg; Hottmann, K. et al

in Chemical Physics (1997), 220

The photoabsorption spectrum of vinylchloride (C2H3Cl) has been measured using synchrotron radiation and has been analyzed in detail between 8-12 eV photon energy. Valence and virtual valence and Rydberg ... [more ▼]

The photoabsorption spectrum of vinylchloride (C2H3Cl) has been measured using synchrotron radiation and has been analyzed in detail between 8-12 eV photon energy. Valence and virtual valence and Rydberg transitions have been identified and classified. Tentative assignments were based on the ionization energies as measured by He(I)- and threshold photoelectron spectroscopy, as reported in the joined paper. Many features have been identified as being members of vibrational progressions belonging to the observed Rydberg series. [less ▲]

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See detailPhotoabsorption and Photoionization of Mono- and Difluoroethylenes.
Leyh, Bernard ULg; Locht, Robert ULg; Hottmann, K. et al

in Aumayr, F.; Betz, G.; Winter, H. P. (Eds.) XX. ICPEAC: Scientific Programme and Abstracts of Contributed Papers. (1997)

The Vacuum UV photoabsorption spectrum and the threshold photoelectron spectrum of C2H3F and 1,1-C2H2F2 have been measured by using synchrotron radiation. CIS-spectra have been recorded for several ... [more ▼]

The Vacuum UV photoabsorption spectrum and the threshold photoelectron spectrum of C2H3F and 1,1-C2H2F2 have been measured by using synchrotron radiation. CIS-spectra have been recorded for several electronic states of both molecules. [less ▲]

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See detailThe Threshold Photoelectron, CIS- and Photoabsorption Spectra of the Methyl Monohalides (Cl, Br, and I).
Locht, Robert ULg; Leyh, Bernard ULg; Jochims, H.-W. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1996)

The threshold photoelectron, the CIS and the vacuum UV photoabsorption spectra of the Methyl halides CH3X (X=Cl,Br and I) were measured by using synchrotron radiation. Several physical magnitudes are ... [more ▼]

The threshold photoelectron, the CIS and the vacuum UV photoabsorption spectra of the Methyl halides CH3X (X=Cl,Br and I) were measured by using synchrotron radiation. Several physical magnitudes are reported. [less ▲]

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See detailThe Threshold Photoelectron and Constant Ion State Spectra of the three Dichloroetylene Isomers.
Leyh, Bernard ULg; Locht, Robert ULg; Hottmann, K. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1996)

Using synchrotron radiation, the threshold phototelectron spectrum and the Constant Ion State (CIS) spectrum of the three isomers of dichloroethylene are reported. Adiabatic ionization energies and ... [more ▼]

Using synchrotron radiation, the threshold phototelectron spectrum and the Constant Ion State (CIS) spectrum of the three isomers of dichloroethylene are reported. Adiabatic ionization energies and vibrational wavenumbers are measured. [less ▲]

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See detailPhotoionization Dynamics of Mono- and Difluoroethylenes.
Leyh, Bernard ULg; Locht, Robert ULg; Hottmann, K. et al

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1995)

Using synchrotron radiation, the threshold photoelectron spectrum and vibrationally resolved CIS-spectra have been recorded between 10-28 eV photon energy for C2H3F and 1,1-C2H2F2.

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See detailResonant Autoionization in Vinylchloride between 10-12 eV.
Locht, Robert ULg; Leyh, Bernard ULg; Hottmann, K. et al

Book published by Berliner Elektronen Speischerring für Synchrotron Strahlung m.b.H (1995)

The threshold photoelectron spectrum of Vinylchloride has been recorded using synchrotron radiation. The attention is focussed on the abundant fine structure between 10-12 eV and has been assigned to ... [more ▼]

The threshold photoelectron spectrum of Vinylchloride has been recorded using synchrotron radiation. The attention is focussed on the abundant fine structure between 10-12 eV and has been assigned to vibrational autoinization. [less ▲]

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See detailThe OCS Molecule. The Photoabsorption Spectrum. The Threshold Photoelectron and CIS-photoelectron Spectra.
Locht, Robert ULg; Hottmann, K.; Baumgärtel, H.

Book published by Berliner Elektronen Speicherring für Synchrotron Strahlung m.b.H (1994)

Using synchrotron radiation the threshold-, the CIS- and the 21.22 eV-photoelectron spectra are reported. This investigation has been completed by recording the VUV photoabsorption spectrum.

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See detailThe Absorption Spectrum and the Threshold- and CIS-photoelectron Spectra of CS2.
Locht, Robert ULg; Hottmann, K.; Denzer, W. et al

Book published by Elektronen Speicherring für Synchrotron Strahlung m.b.H (1993)

Using synchrotron radiation the VUV photoabsorption, the threshold photoelectron and the CIS-photoelctron spectra are measured between 9.9-17.9 eV and are briefly discussed.

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