$CONTRL SCFTYP=RHF RUNTYP=RSURFACE NZVAR=24 $END
 $SYSTEM TIMLIM=100 MWORDS=10 $END
 $BASIS GBASIS=STO NGAUSS=3 $END
 $STATPT NSTEP=200 $END
! TO USE GDIIS FOR GEOMETRY SEARCH (RECOMMENDED OPTION)
 $STATPT  METHOD=GDIIS $END
! TO ALLOW REGENERATION OF DLCs EVERY 5 STEPS AS NEEDED AND/OR
! WHEN THEY BECOME BADLY DEFINED
 $STATPT  NOREG=5 $END
 $SURF NDISP1=5 DISP1=0.01 IVEC1(1)=2,1 IGRP1(1)=1 ORIG1=0 $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)=1,1,2 $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 NONVDW(1)=1,2 $END
 $DATA
Butadiene
 C1
 C   6.0       -1.481450   -0.583385    0.188625
 C   6.0       -0.723784    0.516553    0.061501
 C   6.0        0.589576    0.530702   -0.220831
 C   6.0        1.455228   -0.458012    0.049682
 H   1.0       -1.084939   -1.603704    0.065897
 H   1.0       -2.556345   -0.499052    0.419335
 H   1.0       -1.225062    1.492569    0.187823
 H   1.0        0.993524    1.437189   -0.705543
 H   1.0        1.159982   -1.396368    0.545304
 H   1.0        2.520570   -0.357575   -0.216207
 $END