Coherent structural trapping through wave packet dispersion during photoinduced spin state switching

摘要: The description of ultrafast nonadiabatic chemical dynamics during molecular photo-transformations remains challenging because electronic and nuclear configurations impact each other cannot be treated independently. Here we gain experimental insights, beyond the Born-Oppenheimer approximation, into light-induced spin-state trapping prototypical [Fe(bpy)3](2+) compound by time-resolved X-ray absorption spectroscopy at sub-30-femtosecond resolution high signal-to-noise ratio. decay from initial optically excited state towards spin is distinguished structural dynamics, which launches a coherent oscillating wave packet (265 fs period), clearly identified as breathing. Throughout trapping, dispersion along reaction coordinate reveals details intramolecular vibronic coupling before slower vibrational energy dissipation to solution environment. These findings illustrate how modern can provide key information unravel dynamic photo-functional molecules.