Early summer update

Our building, Rowland Hall, was dedicated as a National Historic Chemical Landmark by the ACS on April 18th, in recognition of the Nobel Prize-winning work performed there by Sherry Rowland and Mario Molina that identified the role of chlorofluorocarbons in stratospheric ozone loss. A two-day symposium was held at the Beckman Center on April 18th–19th to mark the occasion, featuring distinguished guest speakers from academia, and local AirUCI contributions. Kara and Saswata Roy from Prof. Filipp Furche’s group gave a great joint TED-style presentation explaining how a combination of experiment and theory can provide insights into molecular photochemistry.

On May 12th, we attended the 34th Informal Symposium on Kinetics and Photochemical Processes in the Atmosphere held at UCSD. I gave a talk describing some of our work on the reactions of Criegee intermediates with trace atmospheric gases, Sara presented a poster on the same, and Kara loitered networked. Aside from learning some exciting new science, we also discovered that the tacos at Puesto in La Jolla are excellent.

Finally, we bade a fond farewell to Ben who has moved on to pastures new. This month he begins a post-doctoral position at Lawrence Berkeley National Lab, working with Dr. Oliver Gessner and Prof. Steve Leone in the Ultrafast X-Ray Science Laboratory. We wish him all the best in the Bay Area and have no doubt that he will be tremendously successful there.

PCSD 2017

Last week Craig, Kara, and Liz traveled to Asilomar, CA to attend the Pacific Conference on Spectroscopy and Dynamics 2017.  Luck was on our side and we were not swept away by a tsunami or mudslide!

In the poster sessions Craig and Kara presented “Competing Pathways in the Near-UV Photochemistry of Acetaldehyde” and “UV photodissociation dynamics of CHI2Cl and its role as a photolytic precursor for a chlorinated Criegee intermediate”.

Liz presented a talk entitled “Direct Kinetics Measurements and Atmospheric Implications of the Reactions between Criegee Intermediates and Tropospheric Pollutants”.

NSF research grant awarded

NSF LogoWe have been awarded $396,693 by the Chemistry Divison of the National Science Foundation for a three-year project titled, “Unravelling Unconventional photochemistry using time- and state-resolved imaging.” The grant will support our fundamental photochemistry research, in which we use velocity-map ion imaging to explore ‘unusual’ photochemical mechanisms in small molecules.

OCS PHOFEX paper published in J. Phys. Chem. A

OCS PHOFEXOur new paper published in J. Phys. Chem. A uses PHOtoFragment EXcitation (PHOFEX) spectroscopy to pick apart the first absorption band of OCS, the most abundant sulfur-containing molecule in the atmosphere. The PHOFEX spectra obtained probing electronically excited S(1D) and ground state S(3P) atoms are distinctly different; the former is broad and unstructured, while the latter shows distinct resonances that can be attributed to vibrational structure following direct excitation of a quasi-bound triplet state.

The article can be found here: 10.1021/acs.jpca.6b06060

“Hot Paper” in Angewandte Chemie

CH2OO + acids

Our new paper on the kinetics of reactions between the simplest Criegee intermediate, CH2OO, and the inorganic acids HCl and HNO3 has been published as a “hot paper” in Angewandte Chemie International Edition. The reaction with HNO3 in particular is likely to be an important sink in polluted environments. You can read it here: 10.1002/anie.201604662

UPDATE: A news article highlighting our paper has been published on ChemistryViews.

ACS PRF New Directions grant

PRF-LogoWe have been awarded a New Directions grant from the American Chemical Society’s Petroleum Research Fund. The $110,000 award will provide seed funding for a new project titled, “Vibrational Pre-Reactivity: Exploiting Complexes to Probe Reactive Resonances.” We will combine molecular beam techniques with velocity-map ion imaging to study the dynamics of vibrational pre-reaction in atom-molecule van der Waals complexes.

Pair of papers in PCCP

We have two new papers published online in PCCP this week.

Criegee intermediate dynamicsDiiodomethane photochemistry

The first is another collaborative paper with UCI colleague Prof. Benny Gerber and his University of Helsinki team, that follows up on our work on the spectroscopy of the simplest Criegee intermediate, CH2OO. It describes trajectory calculations that explore the excited state dynamics. Read it here: 10.1039/c6cp00807k

The second paper describes a velocity-map ion imaging study of the photodissociation dynamics of diiodomethane (CH2I2). Experimental measurements are interpreted with the help of high-level ab initio calculations by Dr. Grant Hill of the University of Sheffield.  Read it here: 10.1039/c6cp01063f

Criegee intermediate spectroscopy paper published in PCCP

CH2OO B-X spectrum

Our paper on the spectroscopy of the simplest Criegee intermediate, produced in collaboration with UCI colleague Prof. Benny Gerber, has been published in Phys. Chem. Chem. Phys. We have used broadband absorption and cavity ring-down spectroscopy to measure absolute (and temperature-dependent) absorption cross sections for CH2OO in the visible/near UV.

The article can be found here: 10.1039/C5CP04977F