[CPMD-list] isotopes in vibrational analysis

[jernej at cmm.ki.si]

Dear CPMD community,



I am performing a series of harmonic vibrational analyses with CPMD and would
like to study isotope effects. The problem is that I do not know how to change
the atomic mass of one single atom in the molecule. Namely, the ISOTOPE kewyord
in the ATOMS section only allows for changes in atomic masses of *ALL* nuclei
of the same type. This means that, for example, if I specify a value of 2.0 for
hydrogens, all hydrogens in the molecule will be changed to deuteriums. In
contrast to that, my intention is to change only one (or at most two)
hydrogen(s) to deuterium while all other hydrogens should retain a mass of 1.0.
Is this possible in CPMD and if so, what is the appropriate syntax?


Thanks in advance for any help.



Dr. Jernej Stare
National Institute of Chemistry
Ljubljana, Slovenia