BEGIN:VCALENDAR VERSION:2.0 PRODID:-//ZContent.net//ZapCalLib 1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT SUMMARY:Understanding Potential Energy Surfaces Near Conical Intersections with Two-Dimensional Electronic-Vibrational Spectroscopy LOCATION:Chemistry A101 TZID:America/Denver DTSTART:20221110T160000 UID:2026-03-15-23-58-26@natsci.colostate.edu DTSTAMP:20260315T235826 Description:About the Seminar\n\nConical intersections are seams between tw o potential energy surfaces\, at which the degeneracy allows for ultrafast decay to a lower energy state. This connection between potential energy s urfaces is present in many photochemical reactions\, such as the photoisom erization of rhodopsin that is responsible for the initiation of the visua l signaling process.1 Because these reactions occur on sub-picosecond time scales\, ultrafast spectroscopy is one method that has been used to study systems with conical intersections.1 In a recent collaboration between the Fleming and Head-Gordon groups at the University of California\, Berkeley \, the researchers used two-dimensional electronic-vibrational (2DEV) spec troscopy and electronic structure calculations to study crystal violet and malachite green\, two phenylmethane dyes that are known to experience rel axation through conical intersections.2 2DEV spectroscopy provides informa tion about coupling between electronic and vibrational transitions\, as we ll as improved resolution of peaks in 2D spectra compared to other 2D spec troscopy techniques.3 By combining experimental and computational methods\ , the researchers were able to match features of the 2DEV spectra to the g eometries of the dyes at different points along their potential energy sur faces\, showing the complete pathway from photoexcitation to relaxation th rough a conical intersection. Their work demonstrates the ability of 2DEV spectroscopy to provide information about reactions with electronic-vibrat ional coupling\, and offers a comprehensive method for the study of conica l intersections.\n\n \;\n\n Polli\, D. et al.Tracking the primary pho toconversion events in rhodopsins by ultrafast optical spectroscopy. Phot ochem Photobiol Sci14\, 213–228 (2015).\n Wu\, E. et al. Two-dimensiona l electronic-vibrational spectroscopic study of conical intersection dynam ics: an experimental and electronic structure study. Phys. Chem. Chem. Phy s. 21\, 14153-14163 (2019).\n Oliver\, T.\, Lewis\, N.\, Fleming\, G. Cor relating the motion of electrons and nuclei with two-dimensional electroni c–vibrational spectroscopy. Proc Natl Acad Sci USA 111\, 10061-10066 (20 14).\n 4:00 pm END:VEVENT END:VCALENDAR