The role of electronic excited states in the spin-lattice relaxation of spin-1/2 molecules

作者：Lorenzo A. Mariano, Nguyen Vu Ha Anh, Jonatan B. Petersen, Magnus Bjørnsson, Jesper Bendix, Gareth R. Eaton, Sandra S. Eaton, Alessandro Lunghi · 发表于：Science Advances · 年份：2025 · DOI：10.1126/sciadv.adr0168 · 被引用次数：27 · 研究领域：Photochemistry and Electron Transfer Studies、Magnetism in coordination complexes、Advanced Chemical Physics Studies

Magnetic resonance is a prime method for the study of chemical and biological structures and their dynamical processes. The interpretation of many of these experiments relies on understanding how the spin of unpaired electrons exchanges energy with their environment, or lattice, and relaxes to equilibrium. Here, we overcome the common use of effective spin Hamiltonians to describe spin-lattice relaxation in spin-1/2 and apply ab initio open quantum systems theory to their full molecular electronic wavefunction. Simulations for two Cr(V) coordination compounds under this framework show a marked improvement in accuracy and demonstrate that relaxation in spin-1/2 molecules is enabled by virtual transitions to molecular excited states with energy approaching 20,000 cm –1 . This work establishes a connection between the original theory of Van Vleck and modern electronic structure methods, ultimately exemplifying the urgency of further advancing an ab initio approach to spin-lattice relaxation.