Several recent studies have demonstrated how well-suited femtosecond time-resolved photoelectron spectra are for mapping wavepacket dynamics in molecular systems. Theoretical studies of femtosecond photoelectron spectra which incorporate a robust description of the underlying photoionization dynamics should enhance the utility of such spectra as a probe of wavepackets and of the evolution of electronic structure. This should be particularly true in regions of avoided crossings where the photoionization amplitudes and electronic structure may evolve rapidly with geometry. In this paper we present the results of studies of energy- and angle-resolved femtosecond photoelectron spectra for wavepackets in the diatomic systems, Na2 and NaI. Both cases involve motion through regions of avoided crossings. In Na2, however, wavepacket motion occurs on a single adiabatic potential with an inner and outer well and a barrier between them, while in NaI wavepackets move on the nonadiabatically coupled covalent (NaI) and ionic (Na+I-) potentials. Results of these studies will be used to illustrate the insight into wavepacket dynamics that time-resolved photoelectron spectra provide. For example, in the case of NaI these angle-resolved photoelectron spectra seem to offer some promise for probing real-time dynamics of intramolecular electron transfer occurring in the crossing region of the ionic and covalent states.
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J Phys Chem A
January 2025
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
The cyano-cyclopentadiene molecule (CN-CH) has attracted significant interest since its detection in the interstellar medium, but the radical (CN-CH) and anionic (CN-CH) forms of cyano-cyclopentadiene have not been studied. The cyano-cyclopentadienyl radical (CN-Cp) has a strong dipole moment, rendering it an ideal system for vibrational and rotational spectroscopy. We report an investigation of the cryogenically cooled cyano-cyclopentadienide anion (CN-Cp) using high-resolution photoelectron imaging, photodetachment spectroscopy, and resonant photoelectron imaging.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France.
(1,2)--Aminoindanol and (1,2)--aminoindanol, denoted as -AI and -AI, are diastereoisomer aromatic aminoalcohols differing by the presence of a weak intramolecular hydrogen bond in -AI, which is absent in -AI. They also differ by the number of conformers under supersonic jet conditions, one for -AI and two for -AI. One-photon and resonance-enhanced two-photon photoelectron circular dichroism (PECD) spectra are obtained for the two molecules.
View Article and Find Full Text PDFJ Chem Phys
January 2025
School of Chemistry, University of St Andrews, North Haugh, Fife, St Andrews KY16 9ST, United Kingdom.
Two synchrotron-based studies on 4H-pyran-4-thione, photoelectron spectroscopy and vacuum ultraviolet (VUV) absorption spectra were performed. A highly resolved structure was observed in the photoelectron spectrum (PES), in contrast to an earlier PES study, where little structure was observed. The sequence of ionic states was determined using configuration interaction and coupled cluster methods.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
School of Physics and Electronics, Shandong Normal University, 250358 Jinan, China.
Fluorinated graphdiyne (F-GDY) materials exhibit exceptional performance in various applications, such as luminescent devices, electron transport, and energy conversion. Although F-GDY has been successfully synthesized, there is a lack of comprehensive identification of fluorinated configurations, either by theory or experiment. In this work, we investigated seven representative F-GDY configurations with low dopant concentrations and simulated their carbon and fluorine 1s X-ray photoelectron spectroscopy (XPS) and carbon 1s near-edge X-ray absorption fine-structure (NEXAFS) spectra.
View Article and Find Full Text PDFSci Technol Adv Mater
January 2025
Magnetic Functional Device Group, Research Center for Magnetic and Spintronic Materials (CMSM), National Institute for Materials Science (NIMS), Tsukuba, Japan.
We demonstrate high-throughput evaluation of the half-metallicity of CoMnSi Heusler alloys by spin-integrated hard X-ray photoelectron spectroscopy (HAXPES) of composition-spread films performed with high-brilliance synchrotron radiation at NanoTerasu, which identifies the optimum composition showing the best half-metallicity. Co Mn Si composition-spread thin films for = 10-40% with a thickness of 30 nm are fabricated on MgO(100) substrates using combinatorial sputtering technique. The 2-ordering and (001)-oriented epitaxial growth of CoMnSi are confirmed by X-ray diffraction for = 18-40%.
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