Dear all,
I did the optimization and frequency for a system in which contains C,N and H atoms using the following keywords in the input file:
# opt freq=raman b3lyp/6-31g(d,p) pop=full gfinput gfprint iop(6/7=3).
From this calculation, I got 1 imaginary frequency and the calculation was terminated normally. So, I assume that probably this is the transition state. Then I want to include the diffuse function in the basis set then I repeat the same calculation using the following keywords,
# opt freq=raman b3lyp/6-31+g(d,p) pop=full gfinput gfprint iop(6/7=3)
From the latter, I got the following error,
Inaccurate quadrature in CalDSu.
Error termination via Lnk1e in /soft/G09_RevC01/g09/l1002.exe
I already tried the suggestions from the link below but, still got the same error.
https://www.researchgate.net/post/Does_any_one_know_how_to_troubleshoot_an_optimization_terminated_with_error_Inaccurate_quadrature_in_CalDSu
As I understand this related to the integration method and the initial guess wave function used in Gaussian09 (by the default is Harris, CMIIW). Does anyone know how to solve this problem? Any explanations or suggestions are welcomed.
Thank you.
Dear Meilani,
Are you looking for a TS? If so, why are you not using the opt(TS,noeigentest,calcfc) keyword? Do you need the raman spectra? If not, you can try to avoid it with freq=noraman.
Best,
béla
Hi Meilani,
Looks like the calculation is crashing in the coupled perturbed Hartree Fock (CPHF) step. The answer you link to concerns the SCF iteration. It is still relevant but there are some other considerations. The initial guess shouldn't make much difference, for instance, since the SCF iteration has already converged.
First I would just run the calculation with FREQ=NORAMAN as Bela suggested to bypass the problem altogether (even if you need the Raman intensities do it just as a test).
You could also experiment with different grid combinations for SCF and CPHF. By default a coarser grid is used for CPHF (I think). You might be overriding this with INT=ULTRAFINE. Try # INT(GRID=ULTRAFINE) CPHF(GRID=FINE) together for example.
And as Bela also pointed out: If you are looking for a transition state then you should be specifying this with the OPT keyword. If you aren't looking for one then you might need to tweak the geometry to get to a minima.
Hope this helps. I'd be interested to hear what works / doesn't work here.
Gabriel
Hello dear If any of the frequency values are less than zero, these frequencies are known as imaginary frequencies. you should note that image frequency=1 your structure optimize without problem
include keywords opt=tight or Vtight and int=ultrafine
I suggest you to optimize first then do next calculations
Thank you for the answers and suggestions.
Actually I am looking for the minimum structure but, at the end I got 1 imaginary frequency from the previous calculation using the b3lyp/6-31G(d,p). Thus, I realized that this structure is not the minimum one. Since I use b3lyp/6-31+G(d,p) for the other system, hence I repeat the calculation including the diffuse function and end up to this error.
I solved the problem! Thanks Gabriel!! You're right!! It seems the calculation crashed due to the convergence of CPHF. I added the additional keywords "int=(grid=ultrafine)" and "cphf(grid=fine)". I got the same result as without including the diffuse function; 1 imaginary frequency. So, now I can clearly sure that this is not the minimum structure.
Regards,
Meilani
Another thing, different basis set means diferent minima. What is aminima (or TS) in one wont be at the other
In addition to Gabriel's suggestions the other thing you can try for "Error termination via Lnk1e in /soft/G09_RevC01/g09/l1002.exe" type of error is to increase the memory limit. Even if you are not using any you can add some arbitrary value depending on the size of your system. The link mentioned by Meilani suggests that increasing memory didn't help her cause. In my case an ionic liquid system with 73 atoms and a memory limit of 39 MW worked fine.
I could work it out. The problem for this error is the maxdisk. Increase it
Here, an outstanding guide about "How to solve the error message in Gaussian" as follow: https://docs.computecanada.ca/wiki/Gaussian_error_messages
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