Angle determination and scattering suppression in polarization-enhanced two-dimensional infrared spectroscopy in the pump-probe geometry

TLDR: The signal to noise in two-dimensional spectra recorded in the pump-probe geometry can be significantly improved with a quasi-crossed polarizer configuration, often employed in linear dichroism measurements, and the method can be used to selectively suppress individual peaks and to efficiently remove scattering contributions.

Abstract: The signal to noise in two-dimensional spectra recorded in the pump-probe geometry can be significantly improved with a quasi-crossed polarizer configuration, often employed in linear dichroism measurements. Here we examine this method in detail and demonstrate how to analyse and interpret the amplified signals. The angle between transition dipole moments can be determined with better accuracy than in conventional anisotropy measurements, and the method can be used to selectively suppress individual peaks and to efficiently remove scattering contributions. We present spectra of the coupled CO-stretch modes of a Ruthenium-carbonyl complex in DMSO for experimental illustration.