def readMOs(siz):
fil = showFileDialog()
f = open(fil)
lines = f.readlines()
f.close()
mos = MolecularOrbitals(siz)
m = n = 0
for line in lines:
dmval = string.atof(line.strip())
mos.setMatrixAt(m, n, dmval)
n += 1
if (n == siz):
n = 0
m += 1
return mos
