Basically we are trying to calculate the frequency for a particular system but it was stuck in between without showing any error.
We are using Gaussian 09 package for our study. The following lines are the end of the output file.
7 vectors produced by pass120 Test12= 1.54D-13 1.00D-09 XBig12= 1.81D-14 3.66D-09.
7 vectors produced by pass121 Test12= 1.54D-13 1.00D-09 XBig12= 2.33D-14 3.55D-09.
7 vectors produced by pass122 Test12= 1.54D-13 1.00D-09 XBig12= 1.96D-14 3.13D-09.
7 vectors produced by pass123 Test12= 1.54D-13 1.00D-09 XBig12= 2.44D-14 4.10D-09.
7 vectors produced by pass124 Test12= 1.54D-13 1.00D-09 XBig12= 1.99D-14 3.47D-09.
7 vectors produced by pass125 Test12= 1.54D-13 1.00D-09 XBig12= 1.77D-14 2.95D-09.
5 vectors produced by pass126 Test12= 1.54D-13 1.00D-09 XBig12= 1.25D-14 2.62D-09.
Applied DIIS recursively to reduced A of dimension 5074.
It was taking infinite time and no progress at all after these lines. We are actually dealing with a system of 85 atoms and 16 processors, 64 GB of RAM was provided for the same calculation. Our system is Mg-PHE(Pheoforbide systems).
Can anyone please suggest something to come out of this problem? Because it is essential for us to calculate thermochemistry of our systems.
Thank you so much in advance.
This is a known problem in gaussian, that originates from gaussian using two different algorithms for frequency calculations . If the system is too large, gaussian switches to the second algorithm, which is superslow (since it uses disk memory instead of RAM) and often fails.
The solution is to add the following keyword to the input line:
Int=Acc2E=11
which always worked for me (DFT freq for systems of ~100 atoms).
Some people reported also that adding instead:
CPHF(MaxInv=10000)
also solves the problem, though I never used it.
This is a known problem in gaussian, that originates from gaussian using two different algorithms for frequency calculations . If the system is too large, gaussian switches to the second algorithm, which is superslow (since it uses disk memory instead of RAM) and often fails.
The solution is to add the following keyword to the input line:
Int=Acc2E=11
which always worked for me (DFT freq for systems of ~100 atoms).
Some people reported also that adding instead:
CPHF(MaxInv=10000)
also solves the problem, though I never used it.
Dear Prof. Bartosz Trzaskowski,
Thank you so much for your reply. Now it became easy to calculate frequency for my systems. But this Int=Acc2E=11keyword is applicable only for Neutral molecules? Because for me it is taking longer time even more than the previous calcultaions for +ve and -Ve charge containing molecules which has 85 atoms .
Would you please suggest anything in this regard?
Please help me.
Thank you in advance.
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