# A frequency calculation is performed using the mobile block Hessian
# (MBH)method. The coordinates in the ATOMS section should be the partially
# optimized coordinates (or the fully optimized coordinates would work too).
# Such geometry optimization will not be discussed here any further. The next
# input for ADF shows how to perform a frequency calculation with MBH.
C 0.000000 0.000000 0.000000
H 0.634671 0.634671 0.634671
H -0.634671 -0.634671 0.634671
H -0.634671 0.634671 -0.634671
H 0.634671 -0.634671 -0.634671
BlockAtoms 1 2 3 4
# The quality of the frequencies/modes depends largely on the block choice. Best
# results are obtained when grouping atoms in a block if those atoms are known
# to form rather rigid structures. For instance, grouping the 11 atoms of
# benzene side group into a block, will usually result in representative
# frequencies. In this example the block choice is only illustrative for the