Research Group

The Finlayson-Pitts research group consists of a combination of graduate students, postdoctoral fellows, undergraduates and visitors from other Universities and Colleges, both local and national/international. This team of researchers work on individual projects involving sea salt chemistry and heterogeneous reactions of oxides of nitrogen, and in some cases, in groups to address particularly complex problems.  Some of the current group members and their research projects follow.

A new project is being launched under sponsorship of the NSF Collaborative Research in Chemistry Program that involves five co-investigators from UCI (Donald Dabdub, Barbara Finlayson-Pitts,Benny Gerber, John Hemminger and DougTobias) as well as collaborators from New Zealand (Leon Phillips) and the Czech Republic (Pavel Jungwirth).  The goal is to understand the chemical and physical processes that occur at the air-water interface in systems relevant to the atmosphere, and what role they might play in the troposphere. 

Weihong Wang:

Weihong Wang did her undergraduate degree at the University of Science and Technology of China and her Ph.D. at UC Irvine. 

She has identified several unique, chlorine-containing compounds from the reactions of chlorine atoms with 1,3-butadiene and isoprene [Wang and Finlayson-Pitts, J. Geophys. Res., 106 4939 (2001)]; these can be used as "unique markers" of chlorine atom chemistry in the marine boundary layer where atomic chlorine is generated from sea salt reactions.  She has also carried out relative rate studies of the reactions of chlorine atoms with a variety of organics, including the chlorinated carbonyl products from the 1,3-butadiene-chlorine atom reaction. She is currently carrying out aerosol chamber studies of the reactions of sea salt particles and its components with a variety of gases. Current studies include the reactions of NaCl and NaBr, as well as mixtures of the two, with O₃, OH, NO₃ and N₂O₅. She has also coauthored a paper in press in the Journal of Chemical Education on the measurement of trace metals in cigarette tobacco and ash using inductively coupled plasma with atomic emission spectroscopy.

Some Views of the Aerosol Chamber:

The chamber is 561 L and is constructed of aluminum and stainless steel.  All interior surfaces are coated with halocarbon wax to avoid reactions of the gases and particles with the metals.  Several aerosol generation and measurement systems are interfaced to the chamber that allow us to study particles in the 50 nm to 20 um size range. These include an atomizer, a Collison nebulizer, a differential mobility analyzer, condensation particle counter and an aerosol particle spectrometer.  Reactants, intermediates and products are followed using a combination of FTIR, DOAS and API-MS. The chamber is described in more detail in the article by DeHaan et al., Int. J. Chem. Kinet. 18 343 (1999).

End View Showing Interior and Multiple Light Reflections for DOAS

API-MS Interfaced to Aerosol Chamber:

Lisa Wingen:

Lisa did her undergraduate degree at California State University, Fullerton and her Ph.D. at U.C. Irvine.  She has worked in industry and taught part-time at a local community college.  As a graduate student, she coauthored a paper in the Journal of Chemical Education on the development of an undergraduate laboratory experiment on the HPLC analysis of polycyclic aromatic hydrocarbons (PAH) in cigarette smoke.

Her research has encompassed chlorine atom reaction kinetics, the reaction of O(¹ D⁾ with CO₂ in the presence of N₂ as a possible source of N₂O in the atmosphere, and the heterogeneous reaction of NO₂ with water on surfaces to form HONO.  She currently works on sea salt reactions using the aerosol chamber, as well as on the design, construction and application of a new apparatus to study heterogeneous NOx chemistry using ATR-FTIR to follow the thin surface film chemistry and long path FTIR to follow the gas phase chemistry.

Armando Rivera-Figuero:

Armando is from Puerto Rico where he did his undergraduate degree at the University of Puerto Rico, Rio Piedras.  

He is beginning his fourth year as a graduate student and is working on understanding the kinetics and mechanisms of the reactions of NO₂ and HNO₃ on surfaces that are components of dust particles in the atmosphere.  These materials are also found on many surfaces in the boundary layer in urban atmospheres, such as buildings, soil and concrete, and can participate in heterogeneous chemistry in this layer. Armando uses FTIR as the major tool to probe these reactions as it allows him to follow changes in both the surface and in the gas phase species. He is coauthor of a paper submitted to the Journal of Chemical Education, describing a new laboratory experiment on absorption and fluorescence spectroscopy of polycyclic aromatic hydrocarbons that can be used in undergraduate instrumental analysis or physical chemistry laboratories.

Kevin Ramazan:

Kevin is beginning his third year graduate student.  He did his undergraduate degree at the University of California, Riverside.  

With Dennis Syomin, he is carrying out experimental studies of the formation of HONO from the heterogeneous reaction of NO₂ with water and is developing a comprehensive computer kinetics model for this system.  These studies are examining both the dark reaction as well as the photoenhancement reported earlier by Akimoto and coworkers.  He is working on the design and construction of a new apparatus in which ATR will be used to follow the surface reactions while the gases are simultaneously followed using long path FTIR.  Kevin is coauthor of a paper submitted to the Journal of Chemical Education, describing a new laboratory experiment on absorption and fluorescence spectroscopy of polycyclic aromatic hydrocarbons that can be used in undergraduate instrumental analysis or physical chemistry laboratories.

Rachel Hoffman:

Rachel is a graduate of the University of Wisconsin-La Crosse, and is beginning her fourth year as a graduate student. 

She has carried out Knudsen cell studies of the reactions of N₂O₅ and HNO₃ with NaCl and synthetic sea salt. In these studies, she has used single or fractional layers of salt to avoid the problem of diffusion into the spaces between multiple salt layers that gives rise to uncertainties in the effective available reactive surface area. 

In addition, she has shown that the generation of products can be used to measure the reaction probabilities more accurately than the loss of reactants in some cases. Combined with SEM studies of the particle shapes and sizes, these studies permit a relatively accurate determination of the gas-solid  reaction probabilities.  

Margaret Kaleuati:

Margaret did her undergraduate work at Moravian College and came to UCI from George Washington University.  She is a third year graduate student who is working on the reactions of O₃ and OH with NaCl and NaBr using diffuse reflectance Fourier transform infrared spectrometry (DRIFTS). 

Previous studies [Knipping et al., Science, 288 301 (2000)] using our aerosol chamber had shown that Cl₂ was generated at a surprisingly fast rate from the reaction of OH with NaCl, and a reaction at the interface was postulated; such a reaction would generate the hydroxide ion as a product.  Although we are not able to detect OH^- as a product in those studies, it should be detectable using DRIFTS if sufficient water is present on the salt surface. Margaret is also coauthor of a paper in press in the Journal of Chemical Education, describing an instrumental analysis experiment using three different FTIR techniques: transmission, ATR and DRIFTS.

Ann Louise Sumner:

Ann Louise joined the Finlayson-Pitts group as a postdoctoral fellow after completing her Ph.D. at Purdue University where she carried out field studies of chemistry in snowpacks.

She is studying the amount and nature of water in thin films on various surfaces of interest for laboratory systems as well as the atmosphere.  Understanding these is critical for elucidating the chemistry in these thin water layers that are ubiquitous in the troposphere.  She is also studying NOx chemistry on porous glass surfaces.

Dennis Syomin:

Dennis did his undergraduate degree in Nuclear-Chemical engineering at the Russian Chemical-Technological University in Moscow.  He obtained his Ph.D. from the University of Southern California, where he worked on surface science problems.  He is currently a postdoctoral fellow in the group. 

Dennis is working on the photoenhancement of the heterogeneous NO₂ hydrolysis on borosilicate glass surfaces using FTIR, and on the mechanism of loss of HONO on such surfaces.  He is assisting with the design and construction of the new combined ATR-long path cell apparatus for studying heterogeneous NOx chemistry.

Sherri Hunt:

Sherri completed her Ph.D. at the University of Minnesota, carrying out microwave spectroscopic measurements.  She has just joined the Finlayson-Pitts research group as a postdoctoral fellow and will be working on sea salt reactions using the aerosol chamber. 

Mike Ezell:

Mike is on the faculty at Orange Coast College, a local Community College that is amongst the largest two-year colleges in the U.S. 

He works with the Finlayson-Pitts group in our research programs each summer, and has carried out a variety of kinetics studies on the kinetics of chlorine and OH radical reactions using fast flow discharge systems and a relative rate approach with GC and FTIR detection.  His most recent studies have addressed the reactions of chlorine atoms with organics of biogenic interest such as methyl vinyl ketone and methacrolein, and a series of simple alkenes.

Alisa Ezell Smith:

Alisa graduated recently from California State University, Fullerton, with a Bachelor's degree in Chemistry and a Teaching Credential. 

She has carried out research in the Finlayson-Pitts group during the summers, and plans on teaching high school chemistry.  While an undergraduate, she was awarded an "Outstanding Student Paper Award" from the American Geophysical Union for her poster presentation at a national meeting.  Her research has focused on relative rate measurements for chlorine atom reactions with a variety of organics.

Our Group Mascot:

Our group mascot is a Norwegian troll, kindly provided by Dr. Alf Bjorseth. These trolls are reputed to bring good luck... and "the uglier, the better!" He moves from apparatus to apparatus as needed.  

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