Remaining Unperturbed by the Vibrational Response: Probing Vibrational Coupling, Relaxation, and Solvent Effects with 2D IR Spectroscopy

Understanding molecular function first requires an understanding of their native structuresand fluctuations of their environments. One of the most powerful ways to probe the dynamic behavior of molecular systems in solution is through the use of Two-Dimensional Infrared (2D IR) spectroscopy. 2D IR is an ultrafast laser technique that is capable of probing the vibrational properties and dynamics down to the picosecond or even femtosecond timescales. This technique enables the analysis of vibrational couplings, energy redistribution pathways, and solvation dynamics in real time. The early chapters of this dissertation will provide a semi-rigorous introduction to nonlinearresponse theory and explore newly developed models to more accurately capture the bilinear coupling strengths between vibrational modes. These support experimental and computational studies of vibrational energy flow, structural determination, and solute-solvent interactions. A major focus of the research projects covered in this work will be on Intramolecular Vibrational Energy Redistribution (IVR) on two key systems. The first feature aromatic compounds that incorporate a heavy atom (selenium) as a way to block energy transfer between an azido and cyano vibrational probe. Another involves a terpyridine-aldehyde ligand that is relevant to spin relaxation in single-molecule magnets. In both of these works, 2D IR is utilized to reveal vibrational coupling and energy transfer pathways across the molecular scaffold. The last project that will be discussed is on the detection of localized solvation dynamicsthrough frequency fluctuations correlation functions (FFCFs), where the properties of a cyanamide vibrational probe placed onto a deoxycytidine nucleoside are investigated in a variety of viscous environments. This study not only reveals the relationship between the FFCF decay of the NCN reported and solvent viscosity, but further correlates the decay time directly with the nanoscale solvent dynamics via molecular dynamics (MD) simulations.

Level thesis:degree_level

Doctorate Degree

Year dc:date.issued

2025

Author dc:creator

• Mallon, Christopher

Advisor dc:contributor.advisor

• Tucker, Matthew J

Committee members dc:contributor.committeemember

• White, Thomas G
• Barlas, Yafis
• Leitner, David M
• Rogers, Chris

• Cage Correlation Functions
• Frequency Fluctuation Correlation Functions
• Intramolecular Vibrational Energy Relaxation
• Two Dimensional Infrared
• Vibrational Coupling
• Vibrational Energy Delocalization

Language dc:language.iso

en_US, English

Repository record dc:identifier.uri

https://scholarwolf.unr.edu/handle/11714/11558

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/11558