Dissociative Photodetachment Dynamics of the OH(CH) Anion Complex.

Photoelectron-photofragment coincidence (PPC) measurements on OH(CH) anions at a photon energy of 3.20 eV revealed stable and dissociative photodetachment product channels, OH-CH + e and OH + CH + e, respectively. The main product channel observed was dissociation to the reactants (>67%), OH + CH ( = 0, 1, 2) + e, where vibrational excitation in the C-H stretching modes of the CH photofragments corresponds to a minor channel.

Time-resolved dynamics in iodide-uracil-water clusters upon excitation of the nucleobase.

The dynamics of iodide-uracil-water (I·U·HO) clusters following π-π excitation of the nucleobase are probed using time-resolved photoelectron spectroscopy. Photoexcitation of this cluster at 4.77 eV results in electron transfer from the iodide moiety to the uracil, creating a valence-bound anion within the cross correlation of the pump and probe laser pulses.

Photoelectron-Photofragment Coincidence Studies on the Dissociation Dynamics of the OH-CH Complex.

Photoelectron-photofragment coincidence (PPC) spectroscopy was used to characterize the energetics and dynamics of the OH + CH → HO + CH reaction initiated by photodetachment of the OH(CH) anion complex. PPC measurements at a photon energy of 3.20 eV yielded stable (OH-CH + e) and dissociative (OH + CH (ν or ν, v = 0, 1) + e) channels.

Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling.

A cryogenic octopole accumulation trap (COAT) has been coupled to a photoelectron-photofragment coincidence (PPC) spectrometer allowing for improved control over anion vibrational excitation. The anions are heated and cooled via collisions with buffer gas <17 K. Shorter trapping times (500 μs) prevent thermalization and result in anions with high internal excitation while longer trapping times (80 ms) at cryogenic temperatures thermalize the ions to the temperature of the buffer gas.

Resonance-Mediated Below-Threshold Delayed Photoemission and Non-Franck-Condon Photodissociation of Cold Oxyallyl Anions.

The photoexcitation of cold oxyallyl anions was studied below the adiabatic detachment threshold at a photon energy of 1.60 eV. Photodetachment was observed through two product channels, delayed electron emission from a long-lived anionic state and dissociative photodetachment via absorption of a second photon.

Spectroscopy of Ethylenedione and Ethynediolide: A Reinvestigation.

In an effort to characterize the electronic states of ethylenedione, OCCO, photoelectron-photofragment coincidence (PPC) spectroscopy was applied to measure anions at m/z 56 and 57 using a pulsed discharge of glyoxal vapor and N O. PPC measurements at a photon energy of 3.20 eV yield photoelectron spectra in coincidence with either neutral photofragments or stable neutral products.

Internal energy dependence of the photodissociation dynamics of O using cryogenic photoelectron-photofragment coincidence spectroscopy.

Photoelectron-photofragment coincidence (PPC) spectra of ozonide, O, were measured at 388 nm (E = 3.20 eV) using a newly constructed cryogenic octopole accumulation trap coupled to a PPC spectrometer. The photoelectron spectra reveal three processes consisting of a stable photodetachment channel, and two distinct photodissociation pathways yielding (1) O + O or (2) O + O.