Eckert, S.; Vaz da Cruz, V.; Ochmann, M.; Von Ahnen, I.; Föhlisch, A.; Huse, N.: Breaking the Symmetry of Pyrimidine: Solvent Effects and Core-Excited State Dynamics. The Journal of Physical Chemistry Letters 12 (2021), p. 8637–8643
10.1021/acs.jpclett.1c01865
Open Access Version
Abstract:
Symmetry and its breaking crucially define the chemical properties of molecules and their functionality. Resonant inelastic X-ray scattering is a local electronic structure probe reporting on molecular symmetry and its dynamical breaking within the femtosecond scattering duration. Here, we study pyrimidine, a system from the C2v point group, in an aqueous solution environment, using scattering though its 2a2 resonance. Despite the absence of clean parity selection rules for decay transitions from in-plane orbitals, scattering channels including decay from the 7b2 and 11a1 orbitals with nitrogen lone pair character are a direct probe for molecular symmetry. Computed spectra of explicitly solvated molecules sampled from a molecular dynamics simulation are combined with the results of a quantum dynamical description of the X-ray scattering process. We observe dominant signatures of core-excited Jahn–Teller induced symmetry breaking for resonant excitation. Solvent contributions are separable by shortening of the effective scattering duration through excitation energy detuning.