Continetti Group

Dynamics of Transient Species

Latest Lab News

Dynamics of Four Atom Reactions - Direct and Complex-Forming

F + H2O → HF + OH

Our study of the dynamics of the F + H2O → HF + OH reaction using photoelectron-photofragment coincidence spectroscopy was recently published in Science. The manuscript reports on a combined experiment/theory study of this benchmark 4-atom, 6 degree of freedom system, in collaboration with Prof. Hua Guo and co-workers at the University of New Mexico.

R. Otto, J. Ma, A.W. Ray, J.S. Daluz, J. Li, H. Guo and R.E. Continetti, "Imaging Dynamics on the F + H2O → HF + OH Potential Energy Surfaces from Wells to Barriers", Science 343, 396 (2014).

OH + CO → HOCO → H + CO2

Our PCCP Perspectives manuscript reviewing progress in understanding the HOCO radical and the role it plays as an intermediate in the OH + CO → HOCO → H + CO2 reaction has been published in Physical Chemistry Chemical Physics. This manuscript discusses for the first time our results on cis-trans isomerization and accessing the OH + CO entrance channel, and also places these experiments in the context of the many theoretical advances both on the HOCO potential energy surface and the 6-D quantum dynamics of the bimolecular reaction. C.J. Johnson, R. Otto, and R.E. Continetti "Spectroscopy and Dynamics of the HOCO Radical: Insights into the OH + CO → H + CO2 Reaction" PCCP Accepted manuscript, 2014

Sorry this image is currently unavailable



Sorry this image is currently unavailable

Research Overview

Our research focuses on experimental studies of transient species in the gas phase, with a scope of interest ranging from isolated small radicals and ions to mass-selected nanoparticles and aerosols. To carry out this experimental program, we design and construct coincidence spectrometers, ion trapping devices and novel mass spectrometers. Photoelectron and photofragment spectroscopies, three-dimensional imaging techniques and time-of-flight and charge detection mass spectrometric techniques are all brought to bear in studying the structure, energetics and dynamics of these transient forms of matter.

Reaction Dynamics of Transient Species

Our reaction dynamics experiments employ photoelectron-photofragment coincidence spectroscopy in fast ion beams to study dissociative photodetachment, three-body dissociation dynamics, energetics, and photodissociation of anions. On machine C we are now carrying out these studies using an electrostatic ion beam trap (EIBT). Some of our most important recent results include characterization of the tunneling dynamics of the HOCO radical and the OH + CO → H + CO2 reaction, and our recent results, noted above, on the F + H2O → HF + OH reaction. We are also making progress on studying vibrationally excited anions by photoexcitation with an IR laser prior to injection into the electrostatic ion beam trap.

Electrospray Ionization for Coincidence Spectroscopy

Photoelectron-photofragment coincidence (PPC) spectroscopy is a general technique, but it relies on introducing the precursor anions into the gas phase. To extend this technique to larger systems, including biologically relevant anions and anionic precursors for reactive radicals involved in the combustion chemistry of biofuels, we are building an electrospray ionization source coupled with a hexapole accumulator trap and a 10-stage electrostatic linear accelerator to prepare these samples for PPC experiments.

Aerosol Impact Spectrometry

Our newest apparatus is designed to allow the study of single mass- and charge-selected aerosols and nanoparticles using hypervelocity impact on an inert surface for controlled vaporization, yielding insights into particle depth profiles, impact dynamics and particle phase. This approach, an analog to secondary ion mass spectrometry, in which a known ionic projectile is used to interrogate an unknown surface, should provide an interesting complement to current single-particle analysis techniques. Read more...