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Structure and Dynamics of Small Molecules and Anions: Negative-ion photoelectron spectroscopy

Event Details

Event Dates: 

Wednesday, May 9, 2012 - 9:00am

Speaker Name(s): 

Elisa Miller

Speaker Affiliation(s): 

Lineberger group
Seminar Type/Subject

Event Details & Abstract: 

Photoelectron spectroscopy of ICN– (X̃ 2S+) yields information about the structure and energetics of neutral ICN and the anion, ICN–, by probing transitions to the ground state and first five excited states of neutral ICN.  The first three excited states and a conical intersection region between the 3P0+ and 1P1 states are spectroscopically resolved.  Through thermochemical cycles involving spectrally narrow transitions to the excited states of ICN, the electron affinity of ICN, EA(ICN) = 1.345 (+0.40/-0.20) eV, and the dissociation energy of ICN–,D0(X̃ 2S+ I–CN–) = 0.83 (+0.40/-0.20) eV, are determined. Time-resolved photoelectron spectra of IBr⁻(CO2) are taken to measure the photodissociation dynamics of IBr⁻ following excitation to the A′ 2P1/2 electronic state.  A single CO2 solvent molecule perturbs the dissociation dynamics such that the dissociating IBr⁻ undergoes a charge transfer between I and Br at 350 fs.  Molecular dynamics simulations and high-level ab inito calculations help to elucidate the charge transfer mechanism.  The solvation energy of CO2 and the ability of CO2 to temporarily acquire partial charge as it bends facilitate the charge transfer at an I–Br separation of ~7 Å.