Hello,
Here is the code that I am using to obtain EOM-CCSD with frozen core, but I am unable to obtain any outputs; the calculations are getting stuck at some point. Am I doing something wrong?
"$comment
naph
$end
$molecule
0 1
C -1.2447920 -1.4038958 0.0010519
C -2.4360661 -0.7081483 0.0002546
C -2.4360428 0.7081643 -0.0004050
C -1.2448037 1.4038952 -0.0001649
C 0.0000067 0.7189067 0.0001280
C 1.2448253 1.4038898 -0.0000388
C 2.4360546 0.7081538 -0.0001991
C 2.4360771 -0.7081570 -0.0002948
C 1.2447941 -1.4039018 0.0001276
C 0.0000050 -0.7188880 0.0005166
H -1.2427061 -2.4962119 0.0020359
H -3.3844484 -1.2476265 0.0002216
H -3.3844539 1.2476326 -0.0009898
H -1.2427043 2.4962144 -0.0002964
H 1.2427229 2.4962093 -0.0001908
H 3.3844711 1.2476186 -0.0002617
H 3.3844531 -1.2476401 -0.0007464
H 1.2427072 -2.4962154 -0.0001483
$end
$rem
METHOD eom-ccsd
BASIS cc-pVTZ
MEM_TOTAL 200000
N_FROZEN_CORE = fc
IP_STATES 1
SYMMETRY false
$end
"
This is likely a failure in trying to allocate enough memory. When I run the input, the last thing I see in Q-Chem is
Allocating and initializing 199808MB of RAM (this may take a while)...
but when I check the output from the SLURM batch scheduler it’s clear that it was a memory allocation problem:
[2025-11-17T07:21:34.750] error: Detected 1 oom_kill event in StepId=42017782.batch. Some of the step tasks have been OOM Killed.
I suggest trying this with a smaller basis set, say, cc-pVDZ.
Actually, I was interested in obtaining the results with cc-pVTZ, as a reference. Is there no other way out?
Try the small basis set to verify that it’s a memory problem. Assuming that runs, try increasing MEM_TOTAL for the TZ basis set.
Hi John, thanks. I tried DZ, and it worked. I am trying to run TZ, increasing the memory, let’s see if it works.
I think its not possible, it did not work " Molecular Point Group C1 NOp = 1
Largest Abelian Subgroup C1 NOp = 1
Nuclear Repulsion Energy = 456.65259225 hartrees
There are 34 alpha and 34 beta electrons
Requested basis set is cc-pVTZ
There are 148 shells and 412 basis functions
Total memory of 2000000 MB is distributed as follows:
MEM_STATIC is set to 192 MB
QALLOC/CCMAN JOB total memory use is 1999808 MB
Warning: actual memory use might exceed 2000000 MB
Total QAlloc Memory Limit 2000000 MB
Mega-Array Size 188 MB
MEM_STATIC part 192 MB
A cutoff of 1.0D-14 yielded 9898 shell pairs
There are 76458 function pairs ( 99645 Cartesian)
Smallest overlap matrix eigenvalue = 2.15E-05
Scale SEOQF with 1.000000e-01/1.000000e-01/1.000000e+00
Standard Electronic Orientation quadrupole field applied
Nucleus-field energy = 0.0000000152 hartrees
Guess from superposition of atomic densities
Warning: Energy on first SCF cycle will be non-variational
SAD guess density has 68.000000 electrons
"
That output looks like an SCF failure, not a CCSD problem. The SCF worked just fine for me.
You may also need to specify the CC_MEMORY variable.