David Loertscher - David had his first college-level chemistry classes at Bossier Parish Community College in Shreveport, LA. Later, he graduated with a B.S. degree in Chemistry at BYU-Idaho in Rexburg, ID and joined the Armentrout group shortly thereafter in 2019. He studies lanthanide and transition metal oxidation by O2, N2O, and CO2 using the GIBMS experiment and theory. He is also heavily involved in developing a new ion mobility source for GIBMS using Structures for Lossless Ion Manipulations (SLIM) for use in the collision induced dissociation measurements of specific conformers of small peptides and electronic state chromatography (ESC) experiments. His future work interests vary from metal ion and metal ionic cluster thermochemistry to scientific instrument development and semiconductor manufacturing.
Talley A. Fenn (she/her) - Talley received her B.A. in Chemistry in 2021 from Rollins College. She joined the group in December of 2021. Talley is currently studying the exothermic Tb + O chemi-ionization reaction using guided ion beam tandem mass spectrometry (GIBMS) and theoretical calculations, done through measuring bond dissociation energies of products of lanthanide ion oxidation. She is also evaluating the effect on the thermochemistry and reaction dynamics of metal carbonyl cation dissociation by using different collision partners (Ne, Ar, Kr, Xe) and determining relevant periodic trends of the lanthanide series. Her future work includes coupling an inductively-coupled plasma (ICP) source to GIBMS to study lanthanide excited state chemistry with atmospherically relevant neutrals.
Giorgi Jijieshvili (he/him) - Giorgi received a B.S in Chemistry in 2023 from San Diego State University and joined the group in December of 2023. Giorgi is currently working on the thermodynamics of the deamidation of di- and tripeptides using guided ion beam mass spectrometry (GIBMS) and theoretical calculations. His future research includes ion mobility separation of small peptide conformers using structures for lossless ion manipulation (SLIM).
Gonzalo A. Perez Maldonado – Gonzalo received his B.S. in Chemistry in 2023 from California State University, San Bernardino. He joined the group in December of 2023. Gonzalo is currently studying the thermochemistry of actinide cations with ammonia in the gas phase using guided ion-beam tandem mass spectrometry (GIBMS) and computational methods. Future projects include researching the role of f-orbitals in actinide nitride thermochemistry and experimental reactivity through GIBMS and action spectroscopy studies.
Siao Tong (Marina) Jhu (she/her) - Marina received her B.S. in major of Chemistry and minor of Statistics in 2024 from Brigham Young University - Idaho. She joined the group in June of 2024. Marina is currently studying the thermochemistry and mechanism of deamidation of glutamine-containing dipeptides (GlnGly and GlnVal) using guided ion beam tandem mass spectrometry (GIBMS). Her future work is thermochemistry and mechanism of deamidation for glutamine-containing tripeptides.
Thilini Welikumburala (she/her) - Thilini received her B.S. (Honors) from the University of Sri Jayewardenepura, Sri Lanka in 2023. She joined the group in December 2024. Thilini is currently studying the thermochemistry of actinide sulfides in gas phase using guided ion beam mass spectrometry (GIBMS) and theory.
Satish Kumar (he/him) - Satish obtained his Ph.D. in chemistry from the Indian Institute of ScienceEducation and Research (IISER Pune, India) under the supervision of Prof. Aloke Das in 2022. He joined the group in August 2023 as a postdoctoral researcher. Satish is pursuing an understanding of the reactivity of actinide (mostly U and Th) cations with small neutral molecules in the gas phase. He is currently working on the study of the methane C-H bond and activation of water by the U+ cation using guided ion beam tandem mass spectrometry (GIBMS) and quantum calculations. He is also working on the structural binding preference of transition metal cations with dipeptides containing Gly-His and His-Gly sequences, using the infrared multiple photon dissociation (IRMPD) spectroscopy technique located at the Felix facility (Radboud University, Netherlands), as well as quantum chemical calculations.
Evan Perez (he/him) - Evan received a B.S. in Chemistry from Duquesne University in 2016 and his Ph.D. under Mark Johnson from Yale University in 2022. He joined the Armentrout group in August of 2022. In the Armentrout Group, his research focuses on understanding how peptide size influences gas-phase fragmentation behavior. Using guided ion beam mass spectrometry, he measures threshold fragmentation energies for protonated polyglycine systems. As peptide chains grow longer and structurally more complex, their fragmentation pathways become increasingly diverse. By determining precise energy thresholds across a series of peptide lengths, he can develop mechanistic models that describe how and why these pathways evolve. This work provides fundamental insight into peptide energetics and supports improved interpretation of mass spectrometric analyses of biomolecules.
Left to Right: David Loertscher, Brandon C. Stevenson, Peter B. Armentrout, Talley Fenn. Front Row: Sara Rockow, Fan Yang.
Left to Right: Samantha K. Walker, Brandon C. Stevenson, Peter B. Armentrout, Roland Manning Jones III, and Maryam Ghiassee.
Back row: Chris McNary, Cameron Owen (REU), John Carpenter, Oscar Wheeler, Prof. Murat Citir (former postoc and visitor from Turkey), Lauren Sanchez (REU), Becky Coates. Second row: Randy Hightower, Maria Demireva, Maryam Ghiassee, Chinye Nwokolo (REU). First row: PBA, Elizabeth Christensen, Georgia Boles, Arjun Kafle, JungSoo Kim. Very front row: Fan Yang.
You can contact me at armentrout@chem.utah.edu