Q-Chem fatal error occurred in module 0 and forms2/ShlPairs.C

Hello everyone,
My job is to optimize the geometry of a bromobenzene and an acetone at MP2/cc-pVTZ level, the structure has already been optimized at low level, and a fatal error occurred in my output file:
Q-Chem fatal error occurred in module 0, line 459:

MaxKL too small for Path 2. Use more memory.

Q-Chem fatal error occurred in module forms2/ShlPairs.C, line 54:

In ~ShlPairs: s2Ints != 0.
and I have tried to add the keywords
MEM_TOTAL = 8000
for larger memory, but the error still occurred.
Does anyone can give me some suggesttions?
Thanks a lot!

If you can post a full input file I could give better advice, but some things to try are
(1) MP2 is memory/disk intensive, so suggest increasing memory still more, along with AO2MO_DISK
(2) METHOD=RIMP2 is likely considerably faster. In that case, you need to specify the matching auxiliary basis set (AUX_BASIS = RIMP2-CC-PVTZ)

I double both of these suggestions. Increasing memory to MEM_STATIC=1000 solves the problem with conventional MP2 and cc-pVTZ basis, however using RI-MP2 is recommended for performance reasons.

Thank you very much, a large memory did solve the problem :grinning:

Thank you next time, I will use large MEM_STATIC values.

I’m glad that resolved your problem. However, you really should consider RIMP2 as an alternative. Negligible errors for relative energies and considerably faster, better parallel scaling.