Probing Molecular Structure with Two-Dimensional Infrared Spectroscopy

Abstract

CHEMISTRY

Probing Molecular Structure with Two-Dimensional Infrared Spectroscopy

Two-dimensional infrared spectroscopy (2D IR) provides a powerful tool capable of examining how molecular structure relates to function and how this relationship influences the fundamental chemistry serving as the basis of biological processes. By exploiting the enhanced temporal and spatial resolution allowed by 2D IR in conjunction with site-specific isotope labeling, a series of amphiphilic peptides were synthesized and investigated over the course of their self-assembly into β-sheets. Gaining insight into the mechanisms behind folding and self-assembly can help guide the design of useful nanoscale materials. Hexagonal boron nitride (hBN) was also investigated under 2DIR to observe the upper restrahlen band and assess the feasibility of continuing research into observing upper and lower polariton interactions in addition to tuning the spectral absorption frequency by manipulating the sample tilt angle relative to the incident light. Investigating 2D materials and phonon-polariton interactions under 2D IR may lead to improved infrared optical devices. In addition, influenza A transmembrane (AM2TM) protein was observed under 2D IR to gain insight into the structure of water within its ion channel. Despite the introduction of quasi-crossed polarizer configuration, initial results were not promising due to Mie scattering. A subsequent set of non-crystalline samples were more amenable to spectroscopic measurement.