Exploring the Local Environment Effect on Properties of all-Trans-Retinal by Two-Dimensional Correlation Resonance Raman Spectroscopy

Resonance Raman spectroscopy can provide accurate information on both the excited and ground states. In situ Raman spectra were obtained under different conditions of polarizability and temperature to examine the impact of the external environment on the structure and properties of all-trans-retinal (ATR). The experimental results revealed that the polarizability and temperature affected the stretching vibration modes of C–C and C = C, single and double bonds, respectively. A phase transition occurred at approximately 160 K. Similarly, when the polarizability of the solution reached 0.28, a phase transition was observed. Franck–Condon effect analysis of ATR absorption spectra and Huang–Rhys (HR) factor calculations were performed. The two-dimensional correlation resonance Raman spectroscopy (2DCRRS) was utilized to analyze the changes in the excited state geometry of ATR. This work can serve as a reference for investigating the properties of other \(\uppi\) $\mathrm{\pi }$ -conjugated molecules.