# How to interpret molden AO/MO coefficients?

A simple calculation with Molpro 2012 on H2 molecule in cc-pvtz basis produces a molden file with 28 molecular orbitals. Each MO is defined with 30 AO/MO coefficient, but the number of symmetric AOs is 32, and the number of contractions is 28.

memory, 200, m

basis = cc-pvtz;
symmetry nosym;
geomtyp = xyz;
geometry = {
2

H       0.00000000     0.00000000    -0.46904000
H       0.00000000     0.00000000     0.46904000
}

{rhf;
WF, 2, 1, 0;
}

put, molden, h2.molden;
---


Part of Molpro output

 NUMBER OF PRIMITIVE AOS:          34
NUMBER OF SYMMETRY AOS:           32
NUMBER OF CONTRACTIONS:           28   (  28A   )


Why the number of AO/MO coefficients is not equal to the number of symmetric AOs or the number of contractions?