Figure2 Electrostatic potential of C23-1
The electron excitation process within the probe C23 was analyzed under TDDFT method within the ORCA program. The structure difference between the ground state S0 and lowest excited state S1 were small for all four conformations. The electron density difference between the S0 and S1as shown in Figure3a and Figure3b for C23-1 and C23-4 respectively could show the electron transfer in the excitation process. The electron density difference between the S0 and S1in C23-2 and C23-3 were similar to C23-1 and C23-4 respectively. The electron transfer in the excitation process could be indicated from hole region (h+, orange) to electron region (e-, green) in the figures. As can be seen from Figure3, the electron excitation in the probe C23 should be charge transfer process.