subroutine potn(ik,ne,icn,x,y,z,xci,yci,zci,xn,
     1h1,g1,l,ar,np)
      integer ne,icn(l,3)
      real*8 x(l),y(l),z(l)
      real*8 h1(l),g1(l),xn(l,3),ar
      real*8 xt1,yt1,zt1,xt2,yt2,zt2,xt3,yt3,zt3,aaa
      real*8 c1,c2,c3,xci,yci,zci
      real*8 hh1,gg1
      i1=icn(ik,1)
      j1=icn(ik,2)                                                    
      k1=icn(ik,3)                
      xci=(x(i1)+x(j1)+x(k1))/3.                
      yci=(y(i1)+y(j1)+y(k1))/3.              
      zci=(z(i1)+z(j1)+z(k1))/3.   
      do j=1,ne  
         i1=icn(j,1)
         j1=icn(j,2)                                           
         k1=icn(j,3)                           
         xt1=x(i1)                                       
         yt1=y(i1)                                                  
         zt1=z(i1)         
         xt2=x(j1)                                       
         yt2=y(j1)                                       
         zt2=z(j1)                             
         xt3=x(k1)                                     
         yt3=y(k1)                                 
         zt3=z(k1)           
         h1(j)=0.0                                          
         g1(j)=0.0                                         
         do ll=1,2                                        
            call calgh(xt1,yt1,zt1,xt2,yt2,zt2,xt3,yt3,zt3,i,j,ll,
     1           xci,yci,zci,c1,c2,c3,hh1,gg1,aaa)
            xn(j,1)=c1
            xn(j,2)=c2
            xn(j,3)=c3
            ar=aaa
            h1(j)=h1(j)+hh1                             
            g1(j)=g1(j)+gg1                                             
         enddo
      enddo
      return
      end