Our new paper describing the kinetics of reactions of CH2OO with ketones and diketones has been published in the Journal of Physical Chemistry A. We find rate constants for the β-diketone reactions that are similar to that of acetone, while those for the α-diketones are around 30 times larger. The trends are interpreted using frontier molecular orbital theory.
You can read the paper here: 10.1021/acs.jpca.1c05280
The results of velocity-map imaging experiments characterizing the vibrational predissociation dynamics of HCl dimer have been published in the Journal of Chemical Physics. The free and bound HCl stretch overtones were excited using an infrared laser and the monomer fragments detected using 2+1 REMPI. The correlated product-pair distributions show a strong propensity to maximize rotational excitation and minimize the recoil translational energy. The experimental results are compared with the predictions of various predissociation models.
You can read the paper here: 10.1063/5.0003652
Congratulations to Kara for a successful PhD defense! Despite her poor socialization and bad attitude (I kid…), she gave a great talk and was delighted to receive her ceremonial tool belt – a fitting reward for five years of hard work.
Pre-talk talk
Proudly sporting the ceremonial tool belt
Left to righ: Khanh, Uyen, Alexa, Vahe, Aaron, Kara, Craig
The graduate hooding ceremony took place the following day at the Bren Events Center.
At the ceremony
Allison, Craig, and Kara after the ceremony
Alexa and Zac presented posters at the 36th Informal Symposium on Kinetics and Photochemical Processes in the Atmosphere (ISKPPA), which was held this year at the Center for Environmental Research and Technology at UC Riverside.
Alexa, Kara, Zac, and Craig at ISKPPA
The following week was the 26th UCI Undergraduate Research Symposium, where Uyen, Khanh, and Duy again presented their work on Criegee intermediate reactions. As usual, UROP did an outstanding job organizing a conference that featured 342 oral and 493 presentations from 1267 student presenters who were mentored by 467 UCI faculty, spanning disciplines from across the whole campus.
Zac, Uyen, Khanh, and Duy at UROP
The 2019 Southern California Undergraduate Research Conference (SCURC) was held at Mount Saint Mary’s University in Los Angeles on April 13. Duy, Khanh, and Uyen presented a poster showing some of their recent work looking at the kinetics of Criegee intermediate reactions with ketones.
Duy, Khanh, Uyen, and Craig at the SCURC poster session
We have been awarded $394,638 by the Chemistry Division of the National Science Foundation for a three-year project titled, “Kinetic and Mechanistic Studies of Criegee Intermediate reactivity.” The project is part of the Environmental Chemical Sciences program. We will use laser flash photolysis and broadband transient absorption spectroscopy to measure temperature-dependent rate constants of Criegee intermediate reactions with trace atmospheric gases. Specifically, we will study Criegee intermediate reactions with multifunctional volatile organic compounds, radical species, and explore the influence of humidity on reactivity. A new outreach program will establish air quality and weather monitoring stations at local high schools.
An opportunity is available for a high school chemistry teacher to participate in summer research in Dr. Craig Murray’s laboratory in the Department of Chemistry at the University of California, Irvine (UCI). The Murray Group uses a variety of laser-based spectroscopic techniques to study fundamental photochemistry and reaction kinetics and has a particular interest in processes relevant to atmospheric chemistry. The ‘Teacher-in-Residence’ program comprises two parts:
The ‘Teacher-in-Residence’ program is funded through an NSF award (CHE-1566064). Participants will receive a modest stipend during the summer and costs associated with the class visit will be covered. If you are interested in participating and experiencing a real academic research environment, or have any questions about the program, please contact Craig Murray (craig.murray@uci.edu).
We explore the UV photofragmentation dynamics of acetaldehyde cation in our latest paper published in PCCP. Single-photon VUV ionization was used to prepare cold acetaldehyde cations that are subsequently excited (and fragmented) by UV radiation. The photochemistry is surprisingly rich; we use velocity-map ion imaging to characterize four different photofragmentation channels across a broad range of wavelengths. The experiments are supported by complementary ab initio calculations. The article will appear in a special themed issue of PCCP on Photodissociation and Reaction Dynamics that will be published to celebrate the 65th birthday of former University of Bristol colleague Prof. Mike Ashfold.
You can read the paper here: 10.1039/c8cp06640j
Our latest photodissociation dynamics paper has been published in PCCP. The new paper describes ion imaging and photofragment excitation spectroscopy experiments exploring the photochemistry of acetone. We identify ketene as a new primary photoproduct following excitation to S1 and suggest that a roaming mechanism may be responsible. The radical channel forming methyl and acetyl is characterized over a broad range of wavelengths and is dominated by dissociation on the T1 surface following intersystem crossing. Time-resolved measurements using a ps laser system at 266 nm, find an intersystem crossing rate that is surprisingly around six times slower than in acetaldehyde.
You can read the paper here: 10.1039/c7cp07320h
Our new paper published in J. Phys. Chem. A. combines broadband transient absorption spectroscopy with complementary ab initio calculations to explore the kinetics of the reactions of the simplest Criegee intermediate with a series of alcohols. The results of this study provide new insights into trends in Criegee reactivity.
You can read the paper here: 10.1021/acs.jpca.7b09773