Orientational anisotropy of photoemitting CS2 molecules induced by molecular field splitting

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Bibliographic Details
Title: Orientational anisotropy of photoemitting CS2 molecules induced by molecular field splitting
Authors: Kukk, E., Niskanen, J., Pihlava, L., Granroth, S., Berholts, M., Hafiani, O. H., Stråhlman, Christian, Filosofie doktor, 1987
Source: Journal of Physics B. 58(20)
Subject Terms: molecular photoemission, photoionization, molecular field splitting, photoemission anisotropy, molecular orientation, photoelectron-photoion coincidence, PEPICO
Description: We recorded the sulfur 2p photoelectron spectrum from gas-phase CS2 molecules, in coincidence with the ionic fragments S+, S2+ and CS+. The fragments are created by the dissociation of the parent molecular dication following the Auger decay of the S 2p vacancy. The S 2p photoelectrons were recorded in the direction of the polarization vector of synchrotron radiation at FinEstBeAMS beamline of MAX IV synchrotron, using a hemispherical energy analyzer with sufficiently high resolution to resolve the molecular field splitting effects. The coincident ionic fragments of the linear molecule provided the orientation of the molecular axis of molecules emitting electrons in the polarization direction along the polarization vector of the incident photon beam and we obtained the orientation distributions of these molecules for photoemission from the three spin-orbit and molecular field split components in the S 2p orbital. The molecular field splitting introduced clear differences in the measured orientation distributions. Photoemission along the polarization vector from the 2p orbital with j=1/2,mj=+/- 1/2 created the most isotropic distribution of the emitter molecules, while the distribution corresponding to the 2p orbital with j=3/2,mj=+/- 3/2 was preferredly perpendicular to the polarization vector. Emission from the 2p orbital with j=3/2,mj=+/- 1/2 came from molecules preferably oriented along the polarization vector. We compare these results to previous theoretical predictions with a good quantitative agreement for the components with mj=+/- 1/2. However, the measured anisotropy for the components with mj=+/- 3/2 is somewhat weaker than predicted. This work demonstrates how the electron-ion coincidence technique allows, with high electron energy resolution, for testing photoelectron angular distribution predictions, with the constraint that the polarization vector of the incident photons is parallel to the momentum vector of the photoelectron.
File Description: electronic
Access URL: https://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-80192
https://doi.org/10.1088/1361-6455/ae0a97
Database: SwePub
Description
Abstract:We recorded the sulfur 2p photoelectron spectrum from gas-phase CS2 molecules, in coincidence with the ionic fragments S+, S2+ and CS+. The fragments are created by the dissociation of the parent molecular dication following the Auger decay of the S 2p vacancy. The S 2p photoelectrons were recorded in the direction of the polarization vector of synchrotron radiation at FinEstBeAMS beamline of MAX IV synchrotron, using a hemispherical energy analyzer with sufficiently high resolution to resolve the molecular field splitting effects. The coincident ionic fragments of the linear molecule provided the orientation of the molecular axis of molecules emitting electrons in the polarization direction along the polarization vector of the incident photon beam and we obtained the orientation distributions of these molecules for photoemission from the three spin-orbit and molecular field split components in the S 2p orbital. The molecular field splitting introduced clear differences in the measured orientation distributions. Photoemission along the polarization vector from the 2p orbital with j=1/2,mj=+/- 1/2 created the most isotropic distribution of the emitter molecules, while the distribution corresponding to the 2p orbital with j=3/2,mj=+/- 3/2 was preferredly perpendicular to the polarization vector. Emission from the 2p orbital with j=3/2,mj=+/- 1/2 came from molecules preferably oriented along the polarization vector. We compare these results to previous theoretical predictions with a good quantitative agreement for the components with mj=+/- 1/2. However, the measured anisotropy for the components with mj=+/- 3/2 is somewhat weaker than predicted. This work demonstrates how the electron-ion coincidence technique allows, with high electron energy resolution, for testing photoelectron angular distribution predictions, with the constraint that the polarization vector of the incident photons is parallel to the momentum vector of the photoelectron.
ISSN:09534075
13616455
DOI:10.1088/1361-6455/ae0a97