To demonstrate our proposal, we considered a hydrogen peroxide molecule (H 2 O 2 ). We employed a simulation model consisting of 16∆x × 16∆x × 16∆x grids (∆x = 0.3 Å). We set a H 2 O 2 molecule at the centre of this model. As the initial structure, we considered a situation where all atoms were on the same plane. Then, we solved the equation ( ) with Fourier spectral method with timestep ∆t = 1 fs. Note that we did not include nonbonded potentials because these potentials requie at least three bonds separation for applying. For simulation parameter, we employed Charmm force field parameters. Due to the shortage of a parameter, a conductivity κ = 5.19 × 10 -8 m 2 /(V • s) was taken for all atoms from a mobility of Na+ in water at 298 K the same as the above.