c---------------------------------------------------------------------
      subroutine tnp_respa_step2
c  Step 2 of the velocity Verlet algorithm: update velocities for RESPA
      implicit real*8 (a-h,o-z)
      include 'DIMENSIONS'
      include 'COMMON.CONTROL'
      include 'COMMON.VAR'
      include 'COMMON.MD'
      include 'COMMON.CHAIN'
      include 'COMMON.DERIV'
      include 'COMMON.GEO'
      include 'COMMON.LOCAL'
      include 'COMMON.INTERACT'
      include 'COMMON.IOUNITS'
      include 'COMMON.NAMES'

      double precision d_time_s

ct1      s12_np=s_np
ct2      pistar=pi_np

ct      call kinetic(EK)
ct      HNose1=Hnose(EK,s12_np,potE,pistar,Q_np,t_bath,dimen)
ct      pi_np=pistar+0.5*d_time*(2*EK-dimen*Rb*t_bath)
ct     &                              -0.5*d_time*(HNose1-H0)         

c-------------------------------------
c test of reviewer's comment
      pi_np=pi_np-0.5*d_time*(E_long+Csplit-H0)
cr      print '(a,3f)','2 pi_np,s_np',pi_np,s_np,E_long
c-------------------------------------
      d_time_s=d_time*0.5*s_np

      do j=1,3
        d_t_old(j,0)=d_t_old(j,0)+d_a(j,0)*d_time_s
      enddo
      do i=nnt,nct-1
        do j=1,3
          d_t_old(j,i)=d_t_old(j,i)+d_a(j,i)*d_time_s
        enddo
      enddo
      do i=nnt,nct
        if (itype(i).ne.10) then
          inres=i+nres
          do j=1,3
            d_t_old(j,inres)=d_t_old(j,inres)+d_a(j,inres)*d_time_s
          enddo
        endif
      enddo 

cd      s_np=s12_np

      return
      end