A highly efficient protocol for performing nonadiabatic dynamics simulations is implemented and applied to ultrafast internal conversion and intersystem crossing in various molecules.

Luminescence from Earth-abundant metal ions in solution at room temperature is a very challenging objective due to the intrinsically weak ligand field splitting of first row transition metal ions, which leads to efficient non-radiative deactivation via metal-centered states. Only a handful of 3d n metal complexes (n ≠ 10) show sizeable luminescence at room temperature. Luminescence in the near-infrared spectral region is even more difficult to achieve as further non-radiative pathways come into play. No Earth-abundant first-row transition metal complexes display emission > 1000 nm at room temperature in solution up to now. Here we report the vanadium(III) complex mer-[V(ddpd) 2 ][PF 6 ] 3 yielding phosphorescence around 1100 nm in valeronitrile glass at 77 K as well as at room temperature in acetonitrile with 1.810 -4 % quantum yield (ddpd = N,N '-dimethyl-N,N'-dipyridine-2-ylpyridine-2,6-diamine). In addition, mer-[V(ddpd) 2 ][PF 6 ] 3 shows very strong blue fluorescence with 2 % quantum yield in acetonitrile at room temperature. Our comprehensive study demonstrates that vanadium(III) complexes with d 2 electron configuration constitute a new class of blue and NIR-II luminophores, which complement the classical established complexes of expensive precious metals and rare-earth elements.

The first two excitation bands below 7 eV in the electronic absorption spectrum of maleimide are investigated using a model Hamiltonian including four low-lying singlet excited states within the manifold...

We report an efficient iterative procedure that exploits surface-hopping trajectory methods and quantum dynamics to achieve two complementary purposes: to identify the minimum dimensionality of a molecular Hamiltonian in terms of electronic and nuclear degrees of freedom to study radiationless relaxation mechanisms as well as to provide a reference quantum dynamical calculation that allows assessing of the validity of surface-hopping parameters. This double goal is achieved by a feedback loop between surface hopping and MCTDH calculations based on potential energy surfaces parametrized with a linear vibronic coupling method. Initially, a surface hopping calculation in full dimensionality with a chosen set of parameters is performed, and it is repeated, gradually reducing its dimensionality until divergence with the initial calculation is observed or the system is small enough to be treated quantum dynamically. A comparison between the quantum dynamics and surface hopping simulations dictates the validity of the surface hopping parameters. Using these new parameters, the reduction loop is started again, until convergence. As an example, this strategy is applied to simulate the ultrafast intersystem crossing dynamics of [PtBr 6 ] 2− in solution. The 15-dimensional space initially including 200 electronic states is reduced to a 9-dimensional problem with 76 electronic states, without a considerable loss of accuracy.

No abstract