Carbon 1s photoelectron spectroscopy of the chlorinated methanes: Lifetimes and accurate vibrational lineshape models

Zahl, Maria G.; Børve, Knut J.; Sæthre, Leif J.

doi:10.1016/j.elspec.2012.06.014

Cited by 7 publications

(20 citation statements)

References 86 publications

(88 reference statements)

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“…In the present chapter, some of the most important results from Refs. [1][2][3][4][5] are reported and discussed. Firstly, the role of chlorine as a substituent in each of the three processes core ionization, protonation and electrophilic addition is analyzed.…”

Section: Major Resultsmentioning

confidence: 98%

“…Paper [1]: I performed most of the computations and analyzed the spectra. I wrote a draft for the manuscript, including the figures, and took part in subsequent discussions.…”

Section: Comments On My Own Contributionsmentioning

confidence: 99%

“…[60,61] The validity of the ECP model for computing energies and geometries was explored by a series of hole-state calculations at the HFlevel. [1,2] These were conducted using the Dalton package of programs. [62]…”

Section: Hole-state Calculationsmentioning

confidence: 99%

“…[68,69] Life-time broadening and postcollision interactions are described by the combined function of van der Straten et al [70] The lifetime width was constrained to 100 meV for nonchlorinated carbons [71,72] and reduced by 10 meV per chlorine directly attached to the ionized carbon. [1] The Gaussian width was either a free parameter equal for all atoms or it was constrained to the value obtained from analyzing the CO 2 peak in the calibration spectrum. [1]…”

Section: Overview Of the Franck-condon Analysismentioning

confidence: 99%

“…[1] The Gaussian width was either a free parameter equal for all atoms or it was constrained to the value obtained from analyzing the CO 2 peak in the calibration spectrum. [1]…”

Section: Overview Of the Franck-condon Analysismentioning

confidence: 99%

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Molecular Spectra As a Tool in Assigning Carbon 1s Photoelectron Spectra of Physisorbed Overlayers

et al. 2010

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Section: Major Resultsmentioning

confidence: 98%

“…Paper [1]: I performed most of the computations and analyzed the spectra. I wrote a draft for the manuscript, including the figures, and took part in subsequent discussions.…”

Section: Comments On My Own Contributionsmentioning

confidence: 99%

Section: Hole-state Calculationsmentioning

confidence: 99%

Section: Overview Of the Franck-condon Analysismentioning

confidence: 99%

“…[1] The Gaussian width was either a free parameter equal for all atoms or it was constrained to the value obtained from analyzing the CO 2 peak in the calibration spectrum. [1]…”

Section: Overview Of the Franck-condon Analysismentioning

confidence: 99%

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Molecular Spectra As a Tool in Assigning Carbon 1s Photoelectron Spectra of Physisorbed Overlayers

et al. 2010

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Electronic Properties of Chlorine, Methyl, and Chloromethyl as Substituents to the Ethylene Group—Viewed from the Core of Carbon

et al. 2015

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"Substituent effects" is an important and useful concept in organic chemistry. Although there are many approaches to parametrizing the electronic and steric effects of substituents, the physical basis for the parameters is often unclear. The purpose of the present work is to explore the properties of chemical shifts in carbon 1s energies as a well-defined basis for characterizing substituents to an ethylene C═C moiety. To this end, high-resolution carbon 1s photoelectron spectra of six chloro-substituted ethenes and seven chloro-substituted propenes have been measured in the gas phase. Site-specific adiabatic ionization energies have been determined from the spectra using theoretical ab initio calculations to predict the vibrational structures. For two molecules, 3-chloropropene and 2,3-dichloropropene, the spectral analyses give quantitative results for the conformer populations. The observed shifts have been analyzed in terms of initial-state (potential) and relaxation effects, and charge relaxation has also been analyzed by means of natural resonance theory. On the basis of core-level spectroscopy and models, chlorine, methyl, and chloromethyl have been characterized in terms of their effect on the carbon to which they are attached (α site) as well as the neighboring sp(2) carbon (β site). The derived spectroscopic substituent parameters are characterized by both inductive (electronegativity) effects and the ability of each substituent to engage in electron delocalization via the π system. Moreover, the adopted approach is extended to include substituent-substituent interaction parameters.

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Structure of Self-Assembled Free Methanol/Tetrachloromethane Clusters

2013

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The structure of molecular clusters of diameters at or below a nanometer is important both in nucleation phenomena and potentially for the preparation and application of nanoparticles. Little is known about the relationship between the structure and composition of the cluster and about the interplay between cluster composition, size, and temperature. The present project explores how the structure of mixed CH3OH/CCl4 clusters vary with composition and size; implicitly by changing the amount of noncondensing backing gas and thus the capacity to remove heat during cluster condensation, and explicitly through theoretical models. Experimentally, molecular clusters were produced by coexpansion of helium and a vapor of azeotropic methanol/tetrachloromethane composition in a supersonic nozzle flow. The clusters were subsequently characterized by means of carbon 1s photoelectron spectroscopy. Additional information was obtained by molecular-dynamics simulations of clusters at 3 different sizes, 4 different compositions and several temperatures, and using polarizable force fields. Mixed clusters were indeed obtained in the coexpansion experiments. The clusters show an increasing degree of surface coverage by methanol as the backing pressure is lowered, and at the lowest helium pressure the cluster signal from tetrachloromethane has almost vanished. The MD simulations show a gradual change in cluster structure with increasing methanol contents, from that of isolated rings of methanol at the surface of a tetrachloromethane core, to a contiguous methanol cap covering more than half of the cluster surface, to that of subclusters of tetrachloromethane submerged in a methanol environment. Both experimental and computational results support a thermodynamical driving force for methanol to dominate the surface structure of the mixed clusters. At high helium pressure, the growing clusters may cool efficiently, possibly impeding the diffusion of methanol to the surface. At low helium pressure, methanol is completely dominating the outermost few layers of the clusters, possibly in parts caused by preferential loss of tetrachloromethane through evaporative cooling.

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Carbon 1s photoelectron spectroscopy of the chlorinated methanes: Lifetimes and accurate vibrational lineshape models

Abstract: The present thesis, submitted for the degree of philosophiae doctor at the University of Bergen, consists of a presentation of the methods and main results from five scientific papers. The work has been carried out at the

Cited by 7 publications

References 86 publications

Molecular Spectra As a Tool in Assigning Carbon 1s Photoelectron Spectra of Physisorbed Overlayers

Molecular Spectra As a Tool in Assigning Carbon 1s Photoelectron Spectra of Physisorbed Overlayers

Electronic Properties of Chlorine, Methyl, and Chloromethyl as Substituents to the Ethylene Group—Viewed from the Core of Carbon

Structure of Self-Assembled Free Methanol/Tetrachloromethane Clusters

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