PROGRAM PhaseShift
   USE Numeric_Kinds_Module
   USE Numbers_Module
   USE FileUnits_Common_Module
   USE FileUnits_OneDim_Module
   USE QState_Module
   IMPLICIT NONE
   INTEGER i
   INTEGER, PARAMETER :: N=2**10, Nenergy=100
   REAL(KIND=wp_Kind), PARAMETER :: sigma=2.756d0/0.529177208d0, eps=29.52d0/219474.63d0, rmin=.7*Sigma
   REAL(KIND=wp_Kind), PARAMETER :: rmax=30.d0, emin=eps/1000000, emax=100*(Nenergy+1)*emin, mu=20.1797d0*1822.88839d0/2
   REAL(KIND=wp_Kind) r, v, vp, vpp, hstep
   REAL(KIND=wp_Kind) Pot(0:N), DPot(0:N), DDPot(0:N), Psi(0:N), rvals(0:N), Phase(0:N)
   
   OutDir='E:\ParkerE\PhaseShift\' 
   OPEN(Unit=Out_Unit,File=TRIM(OutDIR)//"Output/PhaseShift.txt")
   WRITE(Screen_Unit,'(2(A,e15.7))')" Sigma= ",sigma," Eps= ",eps
   WRITE(Screen_Unit,'(3(A,e15.7))')" RMin= ",rmin," Rmax= ",rmax," Mu= ",mu
   WRITE(Out_Unit,'(2(A,e15.7))')" Sigma= ",sigma," Eps= ",eps
   WRITE(Out_Unit,'(3(A,e15.7))')" RMin= ",rmin," Rmax= ",rmax," Mu= ",mu
   
   jval=0
   OPEN(UNIT=Pot_Unit,File=TRIM(OutDir)//"GraphicsOut/Potential.csv")
   WRITE(Pot_Unit,'(6A15)')"rvals,  ", "v,  ", "vp,  ", "vpp,  "
   
   hstep=(rmax-rmin)/N   
   DO i=0,N
      r=rmin+hstep*i
      rvals(i)=r
      CALL LJ_Potential(r,v,vp,vpp,sigma,eps)
      Pot(i)=v
      DPot(i)=vp
      DDPot(i)=vpp
      WRITE(Pot_Unit,'(4(e15.7,","))')r,v,vp,vpp
   ENDDO
   
   WRITE(Screen_Unit,*)"-k*rmin=",-SQRT(two*Mu*emin)*rmin
   WRITE(Out_Unit,*)"-k*rmin=",-SQRT(two*Mu*emin)*rmin
   CALL NumerovProp(N, mu, hstep, Pot, Emin, Emax, NEnergy, rvals, Psi, Phase)
   
   CLOSE(Out_Unit)
   STOP "PhaseShift Completed"  
ENDPROGRAM PhaseShift