People

Principal Investigator 

Oliver Gessner, PhD


Group Leader and Leader of the Atomic, Molecular and Optical Sciences (AMOS) Program at Berkeley Lab

Email: OGessner@lbl.gov

Additional Information & CV

Google Scholar


Postdoctoral Fellows

Dr. Debadarshini (Jolly) Mishra


Ph.D. Physics 2024, University of Connecticut   

M.Sc. University of Hyderabad, Hyderabad, India

B.S. St. Xavier’s College, Mumbai, India

Projects: X-ray transient absorption spectroscopy; ultrafast electron diffraction 

Email: dmishra@lbl.gov 

Graduate Students 

Zachery Donnellan, 3rd year Ph.D. Candidate


B.S. Chemistry 2020, West Virginia University 

Project: Time-resolved X-ray photoelectron spectroscopy of light harvesting systems 

Hobbies: Climbing, hiking, video games, reality tv

Email: Zachery_Donnellan@berkeley.edu

Lars Hoffman, 4th year Ph.D. Candidate


B.S. Chemistry 2016, Freie Universität Berlin, Germany

Projects: X-ray transient absorption spectroscopy; ultrafast electron diffraction

Hobbies: Running, hiking, gaming, and esports

Email: LarsHoffmann@lbl.gov 

Undergraduate Students

Gautam Ramkumar


UC Berkeley and Lawrence Berkeley National Laboratory

Projects: Time-resolved X-ray photoelectron spectroscopy of light harvesting systems

Email: gramkumar@lbl.gov 

Melody Li


UC Berkeley and Lawrence Berkeley National Laboratory

Projects: Time-resolved X-ray photoelectron spectroscopy of light harvesting systems; ultrafast electron diffraction

Email: MelodyLi@lbl.gov 

Christian Claudio


UC Berkeley and Lawrence Berkeley National Laboratory

Project: Spectroscopy and imaging of dynamics in helium nanodroplets

Email: CClaudio@lbl.gov 

Recent Alumnae and Alumni 

Dr. Sahan Perera

Air Liquide, Fremont, CA

Ph.D. Chemistry 2019, University of Saskatchewan   

M.Sc. University of Saskatchewan

Project: Time-resolved X-ray photoelectron spectroscopy of light harvesting systems 

Hobbies: Nature photography, board games, and cricket 

Dr. Kin Fung Lai


Ph.D. Physics 2022, Vrije Universiteit Amsterdam   

M.Sc. Chinese University of Hong Kong

Project: X-ray transient absorption spectroscopy of chemical dynamics

Elham Ghanem


B.S. Chemistry 2023, Cal State Univ., East Bay

Project: X-ray transient absorption spectroscopy and ultrafast electron diffraction

Hobbies: Tennis, watching movies

Dr. Catherine Saladrigas

University of Colorado, Boulder CO

Ph.D. 2022, UC Berkeley and Lawrence Berkeley National Laboratory

B.S. Physics 2016, MIT

Project: Spectroscopy and imaging of dynamics in helium nanodroplets

Hobbies: Hiking, kayaking, hotsprings, piano, gluten free cooking 

Dr. Matthew Fraund

Diablo Valley College, Pleasant Hill, CA

Ph.D. University of the Pacific

B.S. Chemistry 2012, UC Berkeley

Project: Time-resolved X-ray photoelectron spectroscopy of light harvesting systems 

Hobbies: Cooking, video games, and tinkering

Chuying Huang

Ph.D. Student, Northwestern University, Evanston, IL

B.S. Chemistry 2022, UC Berkeley

Project: TrXPS, Synchrotron experiments at the ALS, FLASH, SLAC

Hobbies: Travelling

Lida Kaphar

California Department of Public Health 

B.A. MCB Neurobiology 2023, UC Berkeley 

Project: TrXPS, Synchrotron experiments at the ALS, FLASH, SLAC

Hobbies: Taekwondo, sewing, thrifting 

Nathan Helvy


Ph.D. Student, University of Iowa, Iowa City, IA

B.S. Physics and Applied Math 2021, UC Berkeley

Project: Spectroscopy and dynamics in helium droplets

Hobbies: Reading, robotics, D&D, hiking

Alumnae and Alumni