AffiliationUniv Arizona, Dept Chem & Biochem
MetadataShow full item record
PublisherAMER INST PHYSICS
CitationElectron affinity and excited states of methylglyoxal 2017, 147 (1):013934 The Journal of Chemical Physics
JournalThe Journal of Chemical Physics
RightsPublished by AIP Publishing.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractUsing photoelectron imaging spectroscopy, we characterized the anion of methylglyoxal (X(2)A" electronic state) and three lowest electronic states of the neutral methylglyoxal molecule: the closed-shell singlet ground state (X(1)A'), the lowest triplet state (a(3)A"), and the open-shell singlet state (A(1)A"). The adiabatic electron affinity (EA) of the ground state, EA(X(1)A') = 0.87(1) eV, spectroscopically determined for the first time, compares to 1.10(2) eV for unsubstituted glyoxal. The EAs (adiabatic attachment energies) of two excited states of methylglyoxal were also determined: EA(a(3)A") = 3.27(2) eV and EA(A(1)A") = 3.614(9) eV. The photodetachment of the anion to each of these two states produces the neutral species near the respective structural equilibria; hence, the a(3)A" <- X(2)A" and A(1)A" <- X(2)A" photodetachment transitions are dominated by intense peaks at their respective origins. The lowest-energy photodetachment transition, on the other hand, involves significant geometry relaxation in the X(1)A' state, which corresponds to a 60 degrees internal rotation of the methyl group, compared to the anion structure. Accordingly, the X(1)A' <- X(2)A" transition is characterized as a broad, congested band, whose vertical detachment energy, VDE = 1.20(4) eV, significantly exceeds the adiabatic EA. The experimental results are in excellent agreement with the ab initio predictions using several equation-of-motion methodologies, combined with coupled-cluster theory. Published by AIP Publishing.
Note12 month embargo; published online 11 May 2017.
VersionFinal published version
SponsorsU.S. National Science Foundation [CHE-1266152]