# ion

Specify the bulk concentrations of mobile ion species present in the system. This command can be repeated as necessary to specify multiple types of ions; however, only the largest ionic radius is used to determine the ion-accessibility function. The total bulk system of ions must be electroneutral which means the charge densities/concentrations of positive and negative ions must be equal. The syntax is:

    ion charge {charge} conc {conc} radius {radius}

where

`charge`
  Mobile ion species charge (floating point number in ec)
`conc`
  Mobile ion species concentration (floating point number in M)
`radius`
  Mobile ion species radius (floating point number in Å)