Generalized Excess Spectroscopy

Abstract

With a clear enhancement of the apparent resolution of experimentally determined spectra, excess spectroscopy has been developed as a powerful tool to study solution structures and molecular interactions. In the standard procedure of the method, excess spectra are calculated based on the ideal spectra constructed using two pure compounds. This limits the applications of the method when the pure compounds are unstable or their physical state is different from that of the mixtures. To overcome the problem or to extend the application, we propose generalized excess spectroscopy in this work, where the ideal spectrum is evaluated from the spectra of reference mixtures. After deducing the working equations, we performed digital simulation and then applied the novel approach to a binary system consisting of tert-butanol and carbon tetrachloride. Both results illustrated the feasibility and universality of the method.

In Situ Species Analysis of a Lithium-Ion Battery Electrolyte Containing LiTFSI and Propylene Carbonate

“…The salt has attracted tremendous attention for its high chemical and thermal stability, as well as the similar diffusion coefficients of Li + and TFSI – . Excess spectroscopy has been proven to have high apparent resolution so as to be suitable to unveil the details of solution structures. − By combining excess spectroscopy, molecular dynamics simulations, and quantum chemical calculations, we successfully identified 12 species in the model electrolyte solutions. The results could help us to explore the ion transport mechanism and precisely manipulate the electrolyte components.…”

“…Considering that CF 3 is inert and hard to interact with other molecules, the excess peaks are assigned to the different existing forms of SO 2 . It is worth clarifying that the excess spectra in Figure B were derived by using the generalized excess spectroscopic method based on the references x = 0 and 0.4.…”

“…Considering that CF 3 is inert and hard to interact with other molecules, the excess peaks are assigned to the different existing forms of SO 2 . It is worth clarifying that the excess spectra in Figure 3B were derived by using the generalized excess spectroscopic method 35 based on the references x = 0 and 0.4. Two-dimensional correlation spectroscopy (2D-COS), a correlation analysis method that analyzes a series of spectra with an external perturbation, could enhance spectral resolution.…”