energy unit in electrostatic potential cube file

[NUCP2K]

Dear CP2K group,

  I am a new user of CP2K. I obtained an electrostatic potential cube
file using directive %V_HARTREE_CUBE% after the wavefunction
optimization. I am wondering what is the energy unit in the potential
cube file. Is there any way to change the potential output unit?
Please see below for my input file.

  Thank you very much.

Hanning Chen
Postdoctoral Fellow
Northwestern University, Evanston Illinois 60208

Input File:

 &FORCE_EVAL
  METHOD Quickstep
  &DFT
    &MGRID
      CUTOFF 280
    &END MGRID
    &QS
      EPS_DEFAULT 1.0E-10
    &END QS
    &SCF
      SCF_GUESS RESTART
      EPS_SCF 1.0E-6
      MAX_SCF 1000
      &OT
       MINIMIZER DIIS
       PRECONDITIONER FULL_KINETIC
      &END OT
    &END SCF
    &XC
      &XC_FUNCTIONAL PADE
      &END XC_FUNCTIONAL
    &END XC
    &PRINT
     &TOT_DENSITY_CUBE ON
     &END TOT_DENSITY_CUBE
     &V_HARTREE_CUBE ON
     &END V_HARTREE_CUBE
    &END PRINT
  &END DFT
  &SUBSYS
    &CELL
      ABC 30.0 30.0 30.0
    &END CELL
    &COORD
      ..................
    &END COORD
    &KIND C
      BASIS_SET SZV-GTH-PADE
      POTENTIAL GTH-BLYP-q4
    &END KIND
  &END SUBSYS
&END FORCE_EVAL
&GLOBAL
  PROJECT TESTING
  RUN_TYPE ENERGY
&END GLOBAL