c-----------------------------------------------------------------
      subroutine verlet1
c Applying velocity Verlet algorithm - step 1 to coordinates
      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 adt,adt2
        
      do j=1,3
        adt=d_a_old(j,0)*d_time
        adt2=0.5d0*adt
        dc(j,0)=dc_old(j,0)+(d_t_old(j,0)+adt2)*d_time
        d_t_new(j,0)=d_t_old(j,0)+adt2
        d_t(j,0)=d_t_old(j,0)+adt
      enddo
      do i=nnt,nct-1	
        do j=1,3    
          adt=d_a_old(j,i)*d_time
          adt2=0.5d0*adt
          dc(j,i)=dc_old(j,i)+(d_t_old(j,i)+adt2)*d_time
          d_t_new(j,i)=d_t_old(j,i)+adt2
          d_t(j,i)=d_t_old(j,i)+adt
        enddo
      enddo
      do i=nnt,nct
        if (itype(i).ne.10) then
          inres=i+nres
          do j=1,3    
            adt=d_a_old(j,inres)*d_time
            adt2=0.5d0*adt
            dc(j,inres)=dc_old(j,inres)+(d_t_old(j,inres)+adt2)*d_time
            d_t_new(j,inres)=d_t_old(j,inres)+adt2
            d_t(j,inres)=d_t_old(j,inres)+adt
          enddo
        endif      
      enddo 
      return
      end