Two-dimensional infrared (2D IR) spectroscopy is an advanced spectroscopic technique used to study molecular dynamics, structure, and interactions at a very high temporal resolution. In a typical 2D IR experiment, an initial pair of laser pulses excites the molecule, with the delay between them being scanned. The molecule’s response is then measured with subsequent pulses, generating a two-dimensional map that correlates different vibrational frequencies. In this map, each axis represents a vibrational frequency, and cross-peaks reveal interactions between different vibrational modes. These insights allow us to examine details of conformational changes, charge carrier transfer, hydrogen bonding, and other dynamic processes on picosecond to femtosecond timescales.
