VUV-induced dissociation of methylchlorosilanes, studied by electron–ion coincidence spectroscopy

Kukk, E.; Kooser, Kuno; Ha, Dang Trinh; Granroth, Sari; Nõmmiste, E.

doi:10.1088/0953-4075/43/6/065103

Cited by 6 publications

(9 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The combined photon–electron energy resolution of these experiments approaches and for one of these instruments has already gone beyond 1 meV (0.1 kJ mol −1 ). There are several other new PEPICO experiments with significantly lower resolution, namely a Finnish experiment at the Max III synchrotron facility in Sweden,39, 40 a PEPICO built for the Elettra synchrotron in Italy41 and one at the Laboratório Nacional de Luz Síncrotron (LNLS) in Brazil 42…”

Section: Introductionmentioning

confidence: 99%

Modeling unimolecular reactions in photoelectron photoion coincidence experiments

2010

View full text Add to dashboard Cite

A computer program has been developed to model and analyze the data from photoelectron photoion coincidence (PEPICO) spectroscopy experiments. This code has been used during the past 12 years to extract thermochemical and kinetics information for almost a hundred systems, and the results have been published in over forty papers. It models the dissociative photoionization process in the threshold PEPICO experiment by calculating the thermal energy distribution of the neutral molecule, the energy distribution of the molecular ion as a function of the photon energy, and the resolution of the experiment. Parallel or consecutive dissociation paths of the molecular ion and also of the resulting fragment ions are modeled to reproduce the experimental breakdown curves and time-of-flight distributions. The latter are used to extract the experimental dissociation rates. For slow dissociations, either the quasi-exponential fragment peak shapes or, when the mass resolution is insufficient to model the peak shapes explicitly, the center of mass of the peaks can be used to obtain the rate constants. The internal energy distribution of the fragment ions is calculated from the densities of states using the microcanonical formalism to describe consecutive dissociations. Dissociation rates can be calculated by the RRKM, SSACM or VTST rate theories, and can include tunneling effects, as well. Isomerization of the dissociating ions can also be considered using analytical formulae for the dissociation rates either from the original or the isomer ions. The program can optimize the various input parameters to find a good fit to the experimental data, using the downhill simplex algorithm.

show abstract

Section: Introductionmentioning

confidence: 99%

Modeling unimolecular reactions in photoelectron photoion coincidence experiments

2010

View full text Add to dashboard Cite

show abstract

“…In order to provide a systematic link to previous work where a similar technical approach is employed, the determination of appearance energies ( E a ) was done by following the procedure employed by Kukk et al ., where Gaussian fits were used for the energy extraction from CIY curves. The method is used to approximate the zero‐crossing energy for the slope line at point ( E 0 − Γ peak ), where E 0 is the fitted Gaussian line position and Γ peak is the FWHM of the photoline.…”

Section: Resultsmentioning

confidence: 99%

“…The ion-specific data can then be represented in the form of coincident ion yields (CIYs), where the molecular energetics are approached by comparing ionic yields with respect to the coincident electron energies. [25] The coincidence spectra were measured with two similar setups. In addition to the mass spectrometer, the measurement software and data acquisition hardware were different in the valence and Cd4d experiments.…”

Section: Methodsmentioning

confidence: 99%

“…However, more detailed analysis of the energetics is performed by extracting ion‐specific information from the monolithic coincidence data. The ion‐specific data can then be represented in the form of coincident ion yields (CIYs), where the molecular energetics are approached by comparing ionic yields with respect to the coincident electron energies …”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Electron-ion coincidence study of photofragmentation of the CdCl2 molecule

et al. 2011

View full text Add to dashboard Cite

In this work, the photofragmentation subsequent to valence and Cd4d photoionization of cadmium dichloride (CdCl(2)) were studied using He I and synchrotron excitation. The measurements were performed with a photoelectron-photoion coincidence (PEPICO) setup, and the connection between the singly ionized electronic states and cationic fragments was investigated. The valence-ionized states were found to lead to CdCl(2)(+), Cd(+) and CdCl(+). The Cd4d(- 1) states were found to lead only to Cl(+) ions. The observed charge transfer effect between Cd and Cl was concluded to take place due to internal conversion or fluorescence decay to dissociating valence states either directly or through consecutive fragmentation. The fragmentation energetics were investigated with molecular ab initio calculations, and the calculated energies were found to agree with the detected fragment appearances.

show abstract

“…With suitable normalization, the background spectrum may then be subtracted from the coincidence spectra, increasing the accuracy of the coincidence data by mitigating the impact of random coincidences. This methodology was employed in the production of the PEPICO maps and coincident ion yields (CIYs) [40] in this paper. The statistical coincidence data processing has been previously discussed in more detail [41,42].…”

Section: Methodsmentioning

confidence: 99%

Valence electronic structure and photofragmentation of 1,1,1,2-tetrafluoroethane (CF3-CH2F)

et al. 2012

View full text Add to dashboard Cite

The electronic structure and fragmentation of the hydrofluorocarbon compound 1,1,1,2-tetrafluoroethane (CF 3 -CH 2 F) were studied using spectroscopical methods and quantum chemical calculations. Valence photoelectron spectra and the ionic fragmentation products were recorded with synchrotron radiation in the vacuum ultraviolet (VUV) region. The geometric and electronic structures of the CF 3 -CH 2 F molecule were calculated using the complete active space perturbation theory of second order. The calculated vertical ionization energies were used to interpret the experimental photoelectron spectrum. VUV photodissociation of the sample molecule was studied with photoelectron-photoion coincidence spectroscopy. Coincident ion yields are shown for several cations as a function of electron binding energy. The experimental data are discussed in comparison with theory and previous work.

show abstract

VUV-induced dissociation of methylchlorosilanes, studied by electron–ion coincidence spectroscopy

Cited by 6 publications

References 31 publications

Modeling unimolecular reactions in photoelectron photoion coincidence experiments

Modeling unimolecular reactions in photoelectron photoion coincidence experiments

Electron-ion coincidence study of photofragmentation of the CdCl2 molecule

Valence electronic structure and photofragmentation of 1,1,1,2-tetrafluoroethane (CF3-CH2F)

Contact Info

Product

Resources

About