2 The negative logarithm of the apparent electron activity (pe) pe can be calculated by including the apparent activity of electrons in equilibrium calculations of redox half-cell reactions. In practice it is used as an alternative to Eh and at 25 C can be calculated from Eh values expressed in volts by dividing by 0.059 pe eh 2303RT 2.303Rx pe=0.059pe B 00592、The negative logarithm of the apparent electron activity（pe） pe can be calculated by including the apparent activity of electrons in equilibrium calculations of redox half-cell reactions. In practice it is used as an alternative to Eh and at 25°C can be calculated from Eh values expressed in volts by dividing by 0.059