Resolve "Enabling free Maxwell propagation in multisystem mode, part 2/4"

Description

Allow Maxwell propagation with external currents.

News snippet

Allow Maxwell propagation with external currents.

Checklist

• I have checked that my code follows the Octopus coding standards
• I have added tests for all the new features added in this request.

Closes #206 (closed)

src/hamiltonian/energy.F90

@@ -61,6 +61,7 @@ module energy_oct_m
     FLOAT :: delta_xc    !< the XC derivative discontinuity
     FLOAT :: dft_u       !DFT+U contribution
     FLOAT :: int_dft_u !< Int[n v_U]
+    FLOAT :: pt_exchange
 
     !cmplxscl 
     FLOAT :: Imtotal
@@ -111,8 +112,12 @@ contains
     this%ts           = M_ZERO
     this%berry        = M_ZERO
     this%delta_xc     = M_ZERO
+<<<<<<< src/hamiltonian/energy.F90
     this%dft_u        = M_ZERO
     this%int_dft_u    = M_ZERO
+=======
+    this%pt_exchange  = M_ZERO
+>>>>>>> src/hamiltonian/energy.F90
 
     this%Imtotal       = M_ZERO
     this%Imeigenvalues = M_ZERO
@@ -162,8 +167,12 @@ contains
     eout%ts           = ein%ts
     eout%berry        = ein%berry
     eout%delta_xc     = ein%delta_xc
+<<<<<<< src/hamiltonian/energy.F90
     eout%dft_u        = ein%dft_u
     eout%int_dft_u    = ein%int_dft_u
+=======
+    eout%pt_exchange  = ein%pt_exchange
+>>>>>>> src/hamiltonian/energy.F90
 
     eout%Imtotal = ein%Imtotal
     eout%Imeigenvalues = ein%Imeigenvalues