Molecular dynamics simulation of the behaviour of the charged nanodroplet in electrospray

Molecular dynamics simulation method has been used in this Letter to investigate the behaviour of the charged nanodroplet in electrospray ionisation (ESI). The results indicate that: (i) two metastable states of the charged droplet exist after initial fierce fission because of over-charged condition in nitrogen atmosphere; (ii) nitrogen atmosphere accelerates the desolvation procedure, but it cannot lead to complete desolvation; therefore the methods of increasing the gas pressure, relative gas molecular mass and temperature are still needed; (iii) coexistence-area exists in the periphery of the droplet. The value 0.298 was applied to determine the liquid-vapour interface, exceeding which atoms with a local density were assigned to the liquid phase, and then the radius of the droplet was derived.