CCL: Zero-point energy calculations between two species

[WU Yanbin <wuyb02__gmail.com>]

 Dear all,

I'm using MP2/aug-cc-pVDZ to compute the interaction energy
 between two species A and B.
The electronic interaction energy was corrected
 for basis set superposition error by counterpoise method.
 
In order to compare with experimental interaction energy, the zero
 point energy (ZPE) needs to be added to the electronic interaction
 energy.

My question is: 
Should be delta(ZPE) be computed by
 ZPE(A+B)-ZPE(A_B)-ZPE(B_A), or just ZPE(A+B)-Z(A)-Z(B)?
 ZPE(A+B) is the zero point energy for the A+B dimer.
ZPE(A_B) is the zero
 point energy for A, with B as ghost atom. Similar for ZPE(B_A).
ZPE(A) is the
 zero point energy for A monomer. Similar for ZPE(B_A).

 Do let me know if the question is not made clear.

Thank
 you.

Best,
Yanbin