***, Allene geometry optimization using Z-Matrix
 basis=sto-3g

 rcc=1.32 ang
 rch=1.08 ang
 acc=120  degree
 Geometry={C1                       !Z-matrix input
           C2,c1,rcc
           Q1,c1,rcc,c2,45
           C3,c2,rcc,c1,180,q1,0
           h1,c1,rch,c2,acc,q1,0
           h2,c1,rch,c2,acc,h1,180
           h3,c3,rch,c2,acc,h1,90
           h4,c3,rch,c2,acc,h2,90}
 hf
 optg,saveact='allene.act',savexyz='allene.xyz' !default optimization
                                                !using model hessian.
                                                !Save optimized variables
                                                !in file allene.act
                                                !Save optimized geometry
                                                !in xyz style in
                                                !file allene.xyz