A mass spectrometric photoionization study of CH3F. The CH+2, CH+3 and CH2F+ ion formation

Locht, Robert; Momigny, J.; Rühl, E.; Baumgärtel, H.

doi:10.1016/0301-0104(87)80129-5

Cited by 27 publications

(42 citation statements)

References 14 publications

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“…The remaining question is the lack of any CH 3 + signal in the photo-ionization efficiency curve of CH 3 + in the range 14.6-16.25 eV. In work which is still in progress [12], the photo-ionization and dissociation of CH 3 F has been reinvestigated using synchrotron radiation. The CH 3 + photo-ionization efficiency curve recorded in the range 12-25 eV photon energy unambiguously shows the existence of the process with an appearance energy at 14.65 eV.…”

Section: Discussionmentioning

confidence: 99%

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The dissociative ionization of methyl fluoride. The formation of CH2+ and CH3+

Locht

Momigny

1986

International Journal of Mass Spectrometry and Ion Processes

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The decay of ionized CH 3 F was investigated in the CH 2 + and CH 3 + dissociation channels by electro-ionization and fixed-wavelength photo-ionization using the He(I) and Ne(I) resonance lines. The translational energy spectra, ionization efficiency curves and kinetic energy vs. appearance energy diagrams of both ions were measured. Although dissociative autoionization is the prominent dissociation mechanism for the appearance of CH 2 + and CH 3 + , direct dissociative ionization is observed for CH 2 + at 23.4 eV and for CH 3 + at 16.5 eV.

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Section: Discussionmentioning

confidence: 99%

“…These ions are observed in He<I) and Ne(I) photo-ion energy spectra. Furthermore, in photo-ionization work which is still in progress [12], the CH 3 + ions, appearing at 14.5 eV, have been detected. The kinetic energy vs. appearance energy diagram related to the CH 3 + ion formation has been discussed.…”

Section: Discussionmentioning

confidence: 99%

The dissociative ionization of methyl fluoride. The formation of CH2+ and CH3+

Locht

Momigny

1986

International Journal of Mass Spectrometry and Ion Processes

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“…by ion kinetic energy analysis in photoionisation mass spectrometry. 42 It is also interesting to note that the upper-limit value tends toward the accurate value as the size of the halogen atom increases from F to…”

Section: Bond Dissociation Energiesmentioning

confidence: 98%

Vacuum-UV negative photoion spectroscopy of CH3F, CH3Cl and CH3Br

Rogers

Tuckett

Dunn

et al. 2010

Phys. Chem. Chem. Phys.

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Using tunable vacuum-UV radiation from a synchrotron, negative ions are detected by quadrupolar mass spectrometry following photoexcitation of three gaseous halogenated methanes CH 3 X (X = F,Cl,Br). The In common with many quadrupoles, the spectra of m/z 1 (H − ) anions show contributions from all anions, and only for CH 3 Br is it possible to perform the necessary subtraction to obtain the true H − spectrum.The anion cross sections are normalised to vacuum-UV absorption cross sections to obtain quantum yields for their production. The appearance energies of X − and CH 2 X − are used to calculate upper limits to 298 K bond dissociation energies for D o (H 3 C−X) and D o (XH 2 C−H) which are consistent with literature values. The spectra suggest that most of the anions are formed indirectly by crossing of Rydberg states of the parent molecule onto an ion-pair continuum. The one exception is the lowestenergy peak of F − from CH 3 F at 13.4 eV, where its width and lack of structure suggest it may correspond to a direct ion-pair transition.

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“…During the last decade our laboratory paid a lot of attention to the V-UV spectroscopy, the photoelectron spectroscopy [Threshold (TPES), Constant Ion State (CIS) and He-I] and the mass spectro-metric photoionization of the monohalogenated derivatives of methane, i.e., CH 3 F [14][15][16][17], CH 3 C1 [18][19][20], and recently CH 3 Br [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Medium and high resolution vacuum UV photoabsorption spectroscopy of methyl iodide (CH3I) and its deuterated isotopomers CD3I and CH2DI. A Rydberg series analysis

et al. 2009

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The vacuum UV photoabsorption spectrum of CH 3 I has been investigated between 5 eV and 20 eV. Numerous vibronic transitions are observed. In the high 10-20 eV photon energy range weak to very weak diffuse bands are observed and ascribed to electronic transitions from 3a 1 , 1e and 2a 1 to Rydberg orbitals. In the 6-10.5 eV photon energy range more than 200 sharp and strong to weak lines have been observed. Several photon energy ranges were explored under high resolution conditions allowing us to observe many series up to high values of the principal quantum number n. They are assigned to vibration-less Rydberg transitions and classified into two groups converging to the two components of the spin-orbit split X 2 E state of CH 3 I + . These two groups consist of six different Rydberg series, i.e., nsa 1 , npa 1 , npe, nda 1 , nde and nf. A very close correlation has been established between the term values of the Rydberg states in CH 3 I and in Xe for ns, np, nd and nf Rydberg transitions. For the first time, the same measurements have been performed and the interpretation has been proposed for the photoabsorption spectrum of CH 2 DI and CD 3 I in the 6-10.5 eV photon energy range. For these two species, ionization energies are deduced: for the X 2 E 3/2 and X 2 E 1/2 states of CH 2 DI, these are IE ad = 9.544 eV and IE ad = 10.168 eV, respectively, and the corresponding energies are 9.552 eV and 10.173 eV in CD 3 I.

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A mass spectrometric photoionization study of CH3F. The CH+2, CH+3 and CH2F+ ion formation

Cited by 27 publications

References 14 publications

The dissociative ionization of methyl fluoride. The formation of CH2+ and CH3+

The dissociative ionization of methyl fluoride. The formation of CH2+ and CH3+

Vacuum-UV negative photoion spectroscopy of CH3F, CH3Cl and CH3Br

Medium and high resolution vacuum UV photoabsorption spectroscopy of methyl iodide (CH3I) and its deuterated isotopomers CD3I and CH2DI. A Rydberg series analysis

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