How to calculate the heat formation.

Message

wcwang · #1 Post by **wcwang** » Sat Nov 18, 2006 2:55 am

Dear Sir, Could I use vasp to calculate the heat formation? For Eaxample:
2Cu+ +2(OH)-1 = H2O + Cu2O + Heat. (In the solution)
If yes, How to obtain the Cu+, (OH)'s energy. Can I just set one copper atom in POSAR, and set 'NELECT=10 NOT 11'. About (OH)-1, We just set two copper atoms in POSCAR, and set 'NELECT=8 not 7' Is that right? Thanks for help. ?!

#2 Post by **admin** » Tue Nov 21, 2006 3:58 pm

1) the stoichiometry of your eqn is wrong.
2) please be aware of
--) T=0K unless set otherwise (solution?)
--) I do not know how you plan to model the "solution", giving one Cu atom in POSCAR describes a single Cu atom (or ion) in the gas phase (Gamma only, large lattice parameters) or in Cu-bulk. The same holds for OH and H2O.
--) ionic systems (unless there is NO translational periodicity) are divergent (use the multipole correction modes for charged ions and clusters)

#3 Post by **admin** » Tue Nov 21, 2006 3:58 pm

1) the stoichiometry of your eqn is wrong.
2) please be aware of
--) T=0K unless set otherwise (solution?)
--) I do not know how you plan to model the "solution", giving one Cu atom in POSCAR describes a single Cu atom (or ion) in the gas phase (Gamma only, large lattice parameters) or in Cu-bulk. The same holds for OH and H2O.
--) ionic systems (unless there is NO translational periodicity) are divergent (use the multipole correction modes for charged ions and clusters)

wcwang · #4 Post by **wcwang** » Wed Nov 22, 2006 4:57 am

Thanks for the information!!!