#P Becke3LYP/6-31G(d) scf=(tight) opt=(Z-Matrix,tight)

Becke3LYP/6-31G(d) opt min ammonium cation

+1 1
H1
N2  1  r3
H3  2  r3  1  a3
H4  2  r3  1  a3  3  +120.
H5  2  r3  1  a3  3  -120.

r3=1.02943891
a3=109.47228211