Computational studies of small beryllium clusters (Be) predict dramatic, nonmonotonic changes in the bonding mechanisms and per-atom cohesion energies with increasing . To date, experimental tests of these quantum chemistry models are lacking for all but the Be molecule. In the present study, we report spectroscopic data for Be and Be obtained via anion photodetachment spectroscopy. The trimer is predicted to have symmetric equilibrium structures for both the neutral molecule and the anion. Photodetachment spectra reveal transitions that originate from the XA″ ground state and the 1A' electronically excited state. The state symmetries were assigned on the basis of anisotropic photoelectron angular distributions. The neutral and anionic forms of Be are predicted to be tetrahedral. Franck-Condon diagonal photodetachment was observed with a photoelectron angular distribution consistent with the expected BeXA → BeXA transition. The electron affinities of Be and Be were determined to be 11363 ± 60 and 13052 ± 50 cm, respectively.
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http://dx.doi.org/10.1021/acs.jpclett.3c02169 | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry, KAIST, Daejeon 34141, Republic of Korea.
A photodetachment and photoelectron spectroscopic study by employing a cryogenically cooled ion trap combined with a velocity-map imaging setup has been carried out to unravel the vibrational structures and autodetachment dynamics of the dipole-bound states (DBSs) of -, -, and -methylphenolate anions (-, -, and -CHPhO). The electron binding energy of the DBS increases monotonically with the increase of the neutral dipole moment to give respective values of 66 ± 15, 123 ± 18, or 154 ± 14 cm for the -, -, or -isomer. The different electron-donating effects of the methyl moieties in the three geometrically different isomers seem to be reflected in the experiment.
View Article and Find Full Text PDFJ Phys Chem A
December 2024
Department of Chemistry, Durham University, Durham DH1 3LE, United Kingdom.
Photoelectron imaging of the doubly deprotonated ethylenediaminetetraacetic acid dianion (EDTA) at variable wavelengths indicates two electron loss pathways: direct detachment and thermionic emission from monoanions. The structure of EDTA is also investigated by electronic structure calculations, which indicate that EDTA has two intramolecular hydrogen bonds linking a carboxylate and carboxylic acid group at either end of the molecular backbone. The direct detachment feature in the photoelectron spectrum is very broad and provides evidence for a dissociative photodetachment, where decarboxylation occurs rapidly after electron loss.
View Article and Find Full Text PDFJ Chem Phys
December 2024
State Key Laboratory of Precision Spectroscopy, and School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China.
The direct photodetachment and two-photon photodissociation-photodetachment processes of a series of PtIn- (n = 2-5) anions were systematically studied using cryogenic anion photoelectron spectroscopy and first-principles electronic structure calculations. The adiabatic/vertical detachment energies (ADEs/VDEs) of these anions were determined from their 193 nm photoelectron (PE) spectra, i.e.
View Article and Find Full Text PDFJ Phys Chem Lett
December 2024
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
J Phys Chem A
October 2024
Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States.
The photoelectron spectra of cluster anions of superoxide (O) solvated by one molecule of benzoxazole (BzOx) reveal two competing photodetachment mechanisms: a direct photoemission from the solvated cluster core and an indirect pathway involving temporary anion states of benzoxazole accessed via the O·BzOx → O·BzOx charge-transfer transitions. Benzoxazole is a bicyclic unsaturated organic molecule that does not form permanent anions. However, its low-lying vacant π* orbitals permit a resonant capture of the electron emitted from the O cluster core.
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