Nuclear quantum effect and H/D isotope effect in excited state intramolecular proton transfer and electron‐induced intramolecular proton transfer reactions in 8‐hydroxyquinoline

The optimum exponent α (αopt) value in 1s Gaussian type function (GTF) was analyzed to develop nuclear basis function for multicomponent quantum mechanics (MC_QM) calculations, in which nuclear quantum effects are directly included, on electronic excited state. We have demonstrated that the general values proposed for MC_QM calculations (αave) on electronic ground state are also useful for the MC_QM calculations on excited state. In addition, we also analyzed the αopt value for the MC_QM calculation of transition state (TS) structures. Although the αopt values for TS structures are smaller than those for energy‐minimum structures, indicating that the nuclear wavefunction becomes more diffusive at TS, H/D isotope effects in TS structures can be adequately analyzed using the αave values. We have demonstrated that 1s GTF with the αave value is useful for the MC_QM calculation on not only electronic ground state but also excited states and calculation of TS structures. The optimum exponent α value in 1s Gaussian type function was analyzed to develop nuclear basis function for multicomponent quantum mechanics (MC_QM) calculations, in which nuclear quantum effects are directly included, on electronic excited state. The general values proposed for MC_QM calculations on electronic ground state are also useful for the MC_QM calculations on excited state.