Laser-ion beam photodissociation studies of C3H3Br+ and C3H3Cl+

Krailler, R. E.; Russell, David H.

doi:10.1016/0168-1176(85)80007-0

Cited by 9 publications

(13 citation statements)

References 28 publications

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“…The most frequently observed are the cases of direct dissociation in a repulsive excited electronic state [2][3][4][5][6][7][8][9][10][11][12][13][14]. Predissociation via bound-to-repulsive transition has been observed for dissociation of simple molecular cations also [15][16][17][18].…”

mentioning

confidence: 99%

Discovery of long-lived excited electronic states of vinylchloride, vinylbromide, vinyliodide, and acrylonitrile cations

Youn

Choe

Kim

2003

J. Am. Soc. Mass Spectrom.

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Charge exchange technique has been used to detect the presence of long-lived excited electronic states of some monosubstituted ethene cations. The technique is based on the criterion that charge exchange between polyatomic species is efficient only when the energy of reaction is close to zero or negative (⌬E Յ 0), or the exoergicity rule. The Ã 2 A' states of vinylchloride, vinylbromide, vinyliodide, and acrylonitrile cations have been found to have long lifetimes (tens of microsecond or longer) while all the excited electronic states of vinylfluoride cation have been found to undergo rapid dissociation or nonradiative relaxation to the ground state. The long-lived states found are those displaying well-resolved vibrational structures in the photoelectron spectra. In particular, these are the states generated by removal of an electron from the in-plane nonbonding p orbitals of halogens or the in-plane orbital of the triple bond C §N. The present findings are very similar to those for the monosubstituted benzene cations reported previously. T wo assumptions made in the theory of mass spectra, or quasi-equilibrium theory (QET), are rapid conversion from excited to ground electronic states for molecular ions generated by the ionization method used and also rapid intramolecular vibrational redistribution in the ground electronic state. Then statistical treatment to evaluate dissociation rate constants becomes equivalent to the Rice-Ramsperger-Kassel-Marcus (RRKM) theory for unimolecular reaction and is often called RRKM-QET [1]. These two hypotheses have been actively investigated over the years, emphasis having been placed more on the latter than the former.There are some cases where the hypothesis of rapid conversion from an excited to ground electronic states prior to dissociation is not valid. The most frequently observed are the cases of direct dissociation in a repulsive excited electronic state [2][3][4][5][6][7][8][9][10][11][12][13][14]. Predissociation via bound-to-repulsive transition has been observed for dissociation of simple molecular cations also [15][16][17][18]. Dissociation in a bound excited state, or an "isolated" electronic state, has been hardly observed in ionic cases [19 -23]. Hence, searching for isolated electronic states of polyatomic cations remains a mission yet to be fulfilled.In our recent investigation on photodissociation of benzene cation [24], we found evidences for a very long lifetime (30 s or longer) of its Ã 2 E 2g state. In a subsequent work [25], a method based on charge exchange in collision cells of a modified double focusing mass spectrometer was developed for routine search for long-lived excited states with conventional mass spectrometry. Observations made were summarized as a hypothesis termed the exoergicity rule, which states that an energy resonant (⌬E ϭ 0) or exoergic (⌬E Ͻ 0) charge exchange occurs efficiently at low collision energy while endoergic one (⌬E Ͼ 0) is hardly observable.Here RE(A ϩ ) is the recombination energy of A ϩ . RE is equivalent to the ionizat...

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confidence: 99%

Discovery of long-lived excited electronic states of vinylchloride, vinylbromide, vinyliodide, and acrylonitrile cations

Youn

Choe

Kim

2003

J. Am. Soc. Mass Spectrom.

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“…The peak looks dish-topped, in agreement with previous MID studies. 19,20 When He collision gas was introduced into the collision cell which is a part of the electrode assembly, an additional sharp peak appeared in the center of the dish. This shows that the dish-topped peak is a genuine MID profile, not a collision-induced dissociation peak due to the residual gas.…”

Section: Kinetic Energy Release Distribution (Kerd)mentioning

confidence: 99%

“…19,20 In our previous study of this reaction, 1 it was found that reaction (1a) was responsible for the reactions on a microsecond time scale. Through quantum chemical and kinetic calculations, it was proposed that the observed reaction (MID-MIKES) was due to quantum mechanical tunneling occurring below the threshold for the rate-determining isomerization step.…”

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confidence: 99%

“…Occurrence of reaction (1a) on the microsecond time scale has also been reported in previous MID studies, even though the spectra were not completely free from interferences. 19,20 In the present study, dissociation of PGC has been reinvestigated using the MIKES technique. The kinetic energy release distribution (KERD) arising in the dissociation has been determined.…”

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confidence: 99%

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Dissociation dynamics of propargyl chloride molecular ion near the reaction threshold: manifestation of quantum mechanical tunneling

Won

Choe

Kim

2000

Rapid Commun. Mass Spectrom.

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“…Photo-induced dissociation (PID) as a means of inducing the fragmentation of ions has been used with several types of mass spectrometers. McGilvery and Morrison [1] and Krailler and Russell [2,3] have directed the laser beam perpendicularly to the low density ion beam in the interaction region of, respectively, quadrupole and sector mass spectrometers. The low sensitivity with orthogonal excitation they observed was improved by the use of a coaxial geometry which placed a greater number of ions in the laser beam.…”

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confidence: 99%

High Efficiency Photo-Induced Dissociation of Precursor Ions in a Tandem Time-of-Flight Mass Spectrometer

Seeterlin

Vlasak

Beussman

et al. 1993

J. Am. Soc. Mass Spectrom.

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High efficiency photo-induced dissociation (PID) has been demonstrated in a tandem time-of-flight mass spectrometer. This instrument focuses isomass ion packets to temporal and spatial dimensions similar to those of the focused laser pulses from a high power excimer laser. This high density overlap of photons and ions yields highly efficient fragmentation and also provides high resolution selection of specific precursor ion mass-to-charge ratio values. Using 193 nm photon excitation of the molecular ion of bromobenzene (m/z = 1561, fragmentation, collection, and PID efficiencies af 79%, 132%, and 104%, respectively, were obtained. Characteristic fragmentations of toluene, nitrobenzene, acetophenone, triethylamine, N,N-diethylformamide, N-methylacetamide, and cyclohexene have also been demonstrated.

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Laser-ion beam photodissociation studies of C3H3Br+ and C3H3Cl+

Cited by 9 publications

References 28 publications

Discovery of long-lived excited electronic states of vinylchloride, vinylbromide, vinyliodide, and acrylonitrile cations

Discovery of long-lived excited electronic states of vinylchloride, vinylbromide, vinyliodide, and acrylonitrile cations

Dissociation dynamics of propargyl chloride molecular ion near the reaction threshold: manifestation of quantum mechanical tunneling

High Efficiency Photo-Induced Dissociation of Precursor Ions in a Tandem Time-of-Flight Mass Spectrometer

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