O+2 ions dissociation studied by threshold photoelectron–photoion coincidence method

Richard‐Viard, M.; Dutuit, O.; Lavollée, M.; Govers, T.R.; Guyon, P. M.; Durup, J.

doi:10.1063/1.448846

Cited by 78 publications

(56 citation statements)

References 21 publications

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“…In coincidence studies, the same conclusion was found based on the photoelectron-photoion coincidence ͑PEPICO͒ spectroscopy 11 and threshold-PEPICO ͑TPEPICO͒ study. 39 However, most of the studies measured the ␤ m close to the threshold, and modulations due to Rydberg autoionization series to the inner-valence ionization states are very likely to occur in this energy region. Actually, in the PEPICO study, Eland et al 11 described the measured ␤ m near the threshold, which, ranged from 0 to Ϫ1, and had some subtle structures.…”

Section: B Cross Sections and Asymmetry Parameters For The Photoionimentioning

confidence: 99%

Theoretical studies of cross sections and photoelectron angular distributions in the valence photoionization of molecular oxygen

Lin

Lucchese

2002

The Journal of Chemical Physics

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Photoionization from ground state of molecular oxygen leading to a number of 1 g Ϫ1 , 1 u Ϫ1 , 3 g Ϫ1 , and 2 u Ϫ1 ion states have been investigated for photon energies up to 50 eV using the multichannel Schwinger method with configuration interaction. The use of a multichannel approach and correlated targets not only enables us to obtain results in good agreement with experimental data, but also leads to a better understanding of electron correlation effects in these photoionization processes. In addition to numerous Rydberg-type autoionization states that have been identified in the multichannel study, substantial effects of the open-channel coupling have also been found in almost every channel. These effects are evidences of the strong electron correlation in the photoionization dynamics of this system. The most significant interchannel coupling effect exists in the photoionization to the 3 g Ϫ1 channels, in which a complete failure of the single-channel photoionization description is found in the shape resonance process. In contrast to earlier theoretical studies, we found only one shape resonance in the photoionization to the 3 g Ϫ1 channels instead of two separated multiplet-specific shape resonances. A full description of the resonant state requires the inclusion of coupling to other valence photoionization channels. The photoelectron angular distributions have also been computed and compared to the existing experimental data. Good agreement between experiment and theory has been achieved. In this study, we also calculated molecular orientation parameters under the fixed-nuclei approximation, which contain symmetry information about the resonances and outgoing waves and which can be used to characterize the dynamics of the photoionization.

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Section: B Cross Sections and Asymmetry Parameters For The Photoionimentioning

confidence: 99%

Theoretical studies of cross sections and photoelectron angular distributions in the valence photoionization of molecular oxygen

Lin

Lucchese

2002

The Journal of Chemical Physics

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“…A true coin-cidence signal is then the signature of a double-ionization event and will be recorded each time the scanned photon energy goes through the threshold of a double-ion state. A TPESCO spectrum obtained in this way is then the double-ionization analog of threshold photoelectron spectra used in the study of single-ionization processes [21][22][23].…”

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confidence: 99%

Vibrational structure of theO22+ground state observed by threshold photoelectron coincidence spectroscopy

et al. 1992

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Double ionization of O2 induced by photons from a synchrotron radiation source has been studied in an electron-electron coincidence experiment. A new technique has been developed wherein only electrons with near zero energy are detected by use of the penetrating field method. In this way high sensitivity and energy resolution have been attained allowing nineteen vibrational levels of the (>2 2+ ground state to be observed and molecular parameters of this state to be obtained.

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“…10 23.75 eV, respectively. 83 These measurements indicate that the majority of O++O fragments from O2 (c4Eu, v+ = 0), and 1) are produced in the first and second dissociation limits with substantial kinetic energy releases.71, 85 An upper bound of 200 ns was reported by Guyon et a1. 84 for the rd's of Oa (c4Eu , v+ = 0) based on simulation of the TOF TPEPICO spectrum for O+.…”

Section: O2(c4eu V+ = 01)mentioning

confidence: 86%

“…83 The OZ (d4Eg , f4II9) potential curves are predicted to cross that for Oa (B2E9) near its equilibrium distance between v+ = 0 and 1. 78,86 According to previous theoretical calculations, the Oa ( 12Eg) state whose potential energy curve is parallel to that of values for v+ = 0-7 is likely the result of specific intersections between the potential energy surfaces of these dissociative states and that of 02 (B2E9 ).…”

Section: 333)93mentioning

confidence: 98%

“…The O2 (B2E9) state lies significantly above the first dissociation limit [0+(4 S) +0( 3p) at 18.73 eV] and is known to be strongly predissociative . [83][84][85][86] The fact that the energy of O2 (B2E9) is more than 8 eV higher than that of the Oa (X2II9) ground state makes laser spectroscopic study of Oa (B2E9) difficult. Although the O2 (B2E9) -i O2 (A2IIu) transition is optically allowed, the emission from Oa (B2E9 ) has not been observed , suggesting that the predissociative lifetimes (Td's) are significantly shorter than the radiative lifetimes for Oz (B2E9 , v+).…”

Section: Rotational-resolved Pfi-pe Bands Formentioning

confidence: 99%

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Advances in Photoionization and Photoelectron Studies Using Third Generation Synchrotron Radiation and Uv/Vuv Lasers

2000

Photoionization and Photodetachment

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394 Photoionization and Photodetachment Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 09/30/15. For personal use only. Advances in Photoionization and Photoelectron Studies ... 395 2.3.3. Rotational-resolved PFI-PE bands for Oa (b4E9 , 22IIu, B2Ey 2Eu , c4E) 437 2.3.3.1 . O (b4Ey,v += 0-9) 438 2.3.3.2. O2 (B2E; , v+ = 0 -7) 449 2.3.3.3. O (22IIu , 2E,.) 461 2.3.3.4. O9 (c4Eu , v+ = 0,1) 467 2.3.4. Rotational-resolved PFI-PE Bands for H2 (X2E9v+ = 0 -18) 474 2.3.5. Satellite States of Xe+ at 23-25 eV 482 2.4. Threshold Photoelectron-Photoion Coincidence Study 485 2.4.1. SFs+ 485 3. UV/VUV Laser Studies 489 3.1. Experimental Considerations 489 3.1.1. VUV-PIE and VUV-PFI-PE Measurements 489 3.1.2. N2P-PIE and N2P-PFI-PE Measurements 491 3.2. CS2 (X2113 /2,1/2; vi , v2 , v3) 491 3.2.1. Stark and VUV-PIE Spectra 492 3.2.2. VUV-PFI-PE Spectrum 497 3.2.3. Vibronic Band Intensities of VUV-PFI-PE, N2P-PFI-PE, and TPE Spectra 502 3.3. CH3SH+, CH3CH2SH+, and CH3SCH3 503 3.3.1. Ab initio Calculations 504 3.3.2. N2P-PIE and N2P-PFI-PE Spectra for CH3SH and CH3CH2SH 504 3.3.2.1. CH3SH+ 504 3.3.2.2 . CH3CH2SH+ 507 3.3.3. VUV-PFI-PE Spectra of CH3SH and CH3CH2SH 514 3.3.4. VUV-PFI-PE and N2P-PFI-PE Spectra for CH3SCH3 521 4. Conclusions and Future Developments 528 Acknowledgments 531 References 531 Photoionization and Photodetachment Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 09/30/15. For personal use only.Parallel to the development of TPE spectroscopic techniques using cw VUV light sources, photoelectron studies using pulsed laser based techniques have achieved resolutions close to the optical bandwidth by employing the delayed pulsed field ionization (PFI)-photoelectron (PFI-PE) method .7,26,27 This method, pioneered by Dethlef and Schlag , is becoming the method of choice for laser based photoelectron studies . The PFI-PE Photoionization and Photodetachment Downloaded from www.worldscientific.com by NANYANG TECHNOLOGICAL UNIVERSITY on 09/30/15. For personal use only. high-n (n > 100) Rydberg states populated by laser excitation. Since these high-n Rydberg states converge to the IE of interest , the observed PFI-PE peak is slightly below the true IE. In addition to single -photon excitation using VUV lasers, excitation to high-n Rydberg states can also be accomplished by resonant or non-resonant two-photon (N2P) schemes .28,29 The non-resonant two-photon PFI-PE scheme is especially attractive because it only requires a tunable dye laser in the UV range, which is readily available to most modern laboratories . For specific molecular species with IE values below 12 eV, the N2P-PFI-PE scheme is a useful method for highresolution photoelectron measurements. Since the N2P process requires considerable laser fluences, the occurrence of dissociation and multiphoton ionization processes can cause complications in N2P-PFI studies . Significant fragmentation of parent photoions due to absorption of additional photons has been shown to prevent the measurement of the p...

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O+2 ions dissociation studied by threshold photoelectron–photoion coincidence method

Cited by 78 publications

References 21 publications

Theoretical studies of cross sections and photoelectron angular distributions in the valence photoionization of molecular oxygen

Theoretical studies of cross sections and photoelectron angular distributions in the valence photoionization of molecular oxygen

Vibrational structure of theO22+ground state observed by threshold photoelectron coincidence spectroscopy

Advances in Photoionization and Photoelectron Studies Using Third Generation Synchrotron Radiation and Uv/Vuv Lasers

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