[CPMD-list] isotopes in vibrational analysis

[Oleg Yazyev]

Dear Jernej,

The ISOTOPE keyword change masses of all nuclei corresponding to
the same species, not to the same kind (charge) of nuclei.
You can define two species corresponding to same kind of nuclei,
but with different masses. E.g. for the simulation of H-D molecule
you &ATOMS section should look similar to

&ATOMS
ISOTOPE
1.0
2.0

*H.psp
   LMAX=S
   1
   x1 y1 z1

*H.psp
   LMAX=S
   1
   x2 y2 z2

&END

Here you have two species referring to hydrogen atoms which differ
only in masses.

-- 
Best regards,
 Oleg


jcks> Dear CPMD community,



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


jcks> Thanks in advance for any help.



jcks> Dr. Jernej Stare
jcks> National Institute of Chemistry
jcks> Ljubljana, Slovenia


jcks> _______________________________________________
jcks> CPMD-list mailing list
jcks> CPMD-list at cpmd.org
jcks> http://cpmd.org/mailman/listinfo/cpmd-list




______________________________________________________
Oleg Yazyev
Ecole Polytechnique Fédérale de Lausanne (EPFL)
Institut des Sciences et Ingénierie Chimiques
CH-1015 Lausanne (Switzerland)
Tel.: +41 21 693 9881
E-mail: oleg.yazyev at epfl.ch
WWW: http://icmbcu001.epfl.ch/yazyev/index.html
_______________________________________________________