Valence band of S-(-) Methyl Lactate in the gas phase has been studied by synchrotron radiation photoelectron spectroscopy (PES), Circular Dichroism in the Angular Distribution of photoelectrons, and fragmentation. This chiral molecule presents two different functional groups (the hydroxyl and ester group), with three non-equivalent oxygen atoms clearly distinguishable in the photoelectron spectrum. CDAD in photoelectron spectroscopy combines the information of the molecular electronic states with the chiral properties of the molecule. The circular dichroism as a function of the kinetic energy of the photoelectrons, with a rich and complex oscillating dispersion, puts in evidence the sensitivity of the dichroic parameter to the conformational structural properties [1-4]. In Methyl Lactate there is the opportunity to point out the chemistry of the three different oxygen atoms and relate them to the chiral structure. The electronic structure and the conformational contribution in the photoemission profile have been interpreted with the aim of density functional and ab-initio theoretical calculations. Moreover we have studied the Methyl Lactate ionization and fragmentation thresholds in 8.5-35 eV photon energy range with synchrotron radiation, to complete the valence band study
METHYL LACTATE: CIRCULAR DICHROISM IN THE PHOTOELECTRON ANGULAR DISTRIBUTION, IONIZATION AND FRAGMENTATION THRESHOLDS.
Daniele Catone;Stefano Turchini;Giorgio Contini;Tommaso Prosperi;Nicola Zema;
2008
Abstract
Valence band of S-(-) Methyl Lactate in the gas phase has been studied by synchrotron radiation photoelectron spectroscopy (PES), Circular Dichroism in the Angular Distribution of photoelectrons, and fragmentation. This chiral molecule presents two different functional groups (the hydroxyl and ester group), with three non-equivalent oxygen atoms clearly distinguishable in the photoelectron spectrum. CDAD in photoelectron spectroscopy combines the information of the molecular electronic states with the chiral properties of the molecule. The circular dichroism as a function of the kinetic energy of the photoelectrons, with a rich and complex oscillating dispersion, puts in evidence the sensitivity of the dichroic parameter to the conformational structural properties [1-4]. In Methyl Lactate there is the opportunity to point out the chemistry of the three different oxygen atoms and relate them to the chiral structure. The electronic structure and the conformational contribution in the photoemission profile have been interpreted with the aim of density functional and ab-initio theoretical calculations. Moreover we have studied the Methyl Lactate ionization and fragmentation thresholds in 8.5-35 eV photon energy range with synchrotron radiation, to complete the valence band studyI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
