[CPMD-list] isotopes in vibrational analysis

[Balasubramanian Sundaram]

Dear Jernej,
     One trick that you could try is to have separate lines/section (&ATOMS) for 
these special hydrogen atoms. To be doubly sure, you can even copy the 
pseudopotential file for hydrogen to some other name, and use that name under this 
section.
     And then, under the ISOTOPE section, declare the mass of this special 
hydrogen separately.

Cheers,
Bala

jernej at cmm.ki.si wrote:
> 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
> 
> 
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