Mechanism of laser multiphoton ionization-dissociation. A new technique for evaluating the role of neutrals

Pandolfi, R. S.; Gobeli, D. A.; El‐Sayed, Mostafa A.

doi:10.1021/j150613a003

Cited by 30 publications

(6 citation statements)

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“…The answer depends on the laser intensity. In a series of elegant experiments employing quadrupole and time-of-flight mass spectrometers as massselective current detectors, the research groups of Schlag (61), Bernstein (62), El-Sayed (63), and Reilly (64) have shown that at low intensities just electrons and parent molecular cations are produced, but as the laser intensity is increased, the cation rapidly absorbs more photons, undergoing considerable fragmentation. The extent of successive fragmentation depends on the laser intensity and duration.…”

Section: Experimental Methodsmentioning

confidence: 99%

Two-photon molecular spectroscopy

Friedrich¹

1982

J. Chem. Educ.

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Section: Experimental Methodsmentioning

confidence: 99%

Two-photon molecular spectroscopy

Friedrich¹

1982

J. Chem. Educ.

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“…Pandolfi et al 139 have performed experiments designed to examine whether or not neutral fragments ionize and therefore contribute to the overall ion current observed for smaller fragments. This was done through the use of a variable repelling voltage study.…”

Section: Studies Of Polyatomic Moleculesmentioning

confidence: 99%

Laser multiphoton ionization-dissociation mass spectrometry

Gobeli¹,

Yang²,

El‐Sayed³

1985

Chem. Rev.

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101

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“…More details of the apparatus are given elsewhere. 15 The fourth harmonic (266 nm) of a Quanta-Ray DCR Nd Figure 1). This is in contrast to benzene 2 and benzene-d615 where it is possible to produce exclusively the molecular ion in large quantities at moderate laser powers.…”

Section: Experimental Studies Experimentalmentioning

confidence: 99%

Multiphoton Ionization Mass Spectrometric (MPIMS) Study of Phenol: Mechanism of Ionic Fragment Formation

et al. 1983

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Time of flight (TOF) mass spectrometry is used in conjunction with a variable repelling voltage technique to elucidate the mechanism by which phenol ionizes and dissociates under 266 nm pulsed laser irradiation in combination with a 532 nm or 355 nm pulsed laser. The results suggest that, like benzene, the molecular ion is the predominant precursor of all ionic species generated in the process. Predominance of CsH species at relatively low powers confirms the presence of a low energy dissociation channel involving the elimination of CO. The use of a second laser at 532 nm is found to selectively destroy the CsHc (as compared to the parent ion) species. The parent ion is found to be protected from the radiation of the second laser pulse at 532 nm but not at 355 nm if the second laser pulse is delayed by 50 ns. This is explained in terms of relaxation within the parent ion energy levels, the location of a low energy dissociation channel and the wavelengths of the lasers used. The main aspects of the fragmentation pattern are discussed in terms of the statistical theory of Rebentrost and Ben-Shaul.Unlike electron impact mass spectrometry, which commonly uses either quasiequilibrium or RRKM theory to interpret fragmentation patterns, there appears to be no unifying theory which predicts multiphoton ionization-dissociation (MPID) mass spectral results. Instead, three mechanisms have been suggested which attempt to t Part of this work was used in partial fulfillment of the Ph.D Degree of RSP and DAG.

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Mechanism of laser multiphoton ionization-dissociation. A new technique for evaluating the role of neutrals

Cited by 30 publications

References 0 publications

Two-photon molecular spectroscopy

Two-photon molecular spectroscopy

Laser multiphoton ionization-dissociation mass spectrometry

Multiphoton Ionization Mass Spectrometric (MPIMS) Study of Phenol: Mechanism of Ionic Fragment Formation

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