$CONTRL SCFTYP=UHF RUNTYP=rsurface
 !coord=zmt
 NZVAR=21
MAXIT=10000 
 DFTTYP=B3LYP 
 EXETYP=run $END
 $SYSTEM TIMLIM=100 MWORDS=10 $END
 $BASIS GBASIS=TZV
 NFFUNC=1 
 $END
 $STATPT NSTEP=200 $END
! TO USE GDIIS FOR GEOMETRY SEARCH (RECOMMENDED OPTION)
 $STATPT  METHOD=GDIIS ITBMAT=50 $END
! TO ALLOW REGENERATION OF DLCs EVERY 5 STEPS AS NEEDED AND/OR
! WHEN THEY BECOME BADLY DEFINED
 $STATPT  NOREG=5  
 $END
 $SURF NDISP1=50 DISP1=3 ORIG1=1 
 $END
! TO REUSE APPROXIMATE HESSIAN INFORMATION DURING RELAXED SCANS
 $SURF REUSE=.T.  
 $END
 $ZMAT DLC=.T. AUTO=.T. $END
! THE FOLLOWING OPTION IS REQUIRED FOR RELAXED SCANS IN DLCs
 $ZMAT AUTOFV=.T. $END
! TO FREEZE DISTANCE BETWEEN FIRST AND SECOND ATOM
 $ZMAT
  ifzmat(1)=2,2,1,9
  !irzmat(1)=3,9,1,2,3
  !, 3,9,1,2,4
  scan=.t.  
  ifdmod=2
$END
! EXPLICIT SPECIFICATION OF BOND 1-2
! JUST FOR THE CASE IF THE DISTANCE(S) WILL BECOME(S) TOO BIG
! TO BE SELECTED AUTOMATICALLY BY THE DLC GENERATOR DURING SCAN.
!$ZMAT IXZMAT(1)=3,9,1,2,3, 3,9,1,2,4  $END

!============== NONVDW ==============
!-- User defined bond/s --
 $ZMAT
       NONVDW(1)=1,9
 $END
 $DATA
Butadiene
C1
O     8.0     0.00000000    -0.06728908     0.00000024
C     6.0     0.00000000     1.15220284    -0.00000056
N     7.0    -1.16025662     1.88919675    -0.00000010
N     7.0     1.16025662     1.88919675    -0.00000010
H     1.0    -2.02684402     1.38079941     0.00000105
H     1.0     2.02684402     1.38079941     0.00000105
H     1.0    -1.19339943     2.89351535     0.00000173
H     1.0     1.19339943     2.89351535     0.00000173
Ni    28.0     0.00000000    0.00000000     3.00000000
 $END