problem O charges for methyl acetate MP2/AUG-cc-pvdz

[sgarturo]

Good day. I am trying to validate these AIM charge computations against older AIMPAC computations. It looks like I cannot get agreement between the methods for methyl acetate where the .fchk file was made using the MP2/AUG-cc-pvdz level and basis set using Gaussian. The differences can be summarized with the charges on the oxygen atoms.

Using AIMPAC, the carbonyl O-atom has a charge of -1.184. Using your bader code, I get -1.9084.
Using AIMPAC, the ether O-atom has a charge of -1.085. Using your bader code, I get -1.7037.

I created the .cube file with the cubegen utility with option "-4", whcih gave me a grid of 241 x 182 x 157.

To complicate matters, I further compute the volume in au of atoms up to the 0.001 au isodensity surface. And for the O-atoms, I get ok agreement
144 bader vs. 136 AIMPAC for carbonyl O-atom
109 bader vs. 104 AIMPAC for ether O-atom

I really hope I am doing something wrong, because your method is fast enough to be applicable over a wide range of applications.

I'd like to know if you can verify my results using bader.exe for methyl acetate. If you can also use AIMPAC to verify my earlier results too, that would be helpful. if you tell me I am doing something wrong, I'd greatly appreciate it and will continue using your method. Thanks.