To demonstrate our proposal, we calculated the dynamics of ethylene (C 2 H 4 ) by solving the equation ( ) with the time step ∆t = 1 fs. A conductivity κ = 5.19 × 10 -8 m 2 /(V• s) was taken from the mobility of Na + in water at 298 K 10 . For diffusive coefficients, we employed D tr = 1.54 × 10 -9 m 2 /s and D rot = 2.62 × 10 11 rad 2 /s. These values are obtained from the molecular dynamics simulation (Supporting information S3) because the theoretical calculation of diffusive coefficients, that is, the Stokes-Einstein equation breaks down on a molecular scale . For other parameters, we employed Charmm force field parameters .