UT theoretical chemistry code forum

Hello,

Any further explorations would be appreciated.

Thanks

Thank you so much.

I checked carefully the frequencies that I got previously which were using Ibrion6 with isif3. In addition to the last three negative frequencies, there are some small positive frequencies.
I have also tried ibrion8 with isif2 and addgrid. There are also three negative ...

Thank you so much.

Do you mean that: continue with contcar (of old sigma) and the new sigma to re-optimize the structure and calculate the frequencies until convergence? With this I see only one ionic step and no further ionic relaxation for my structure.

With entropy less than about 1meV/atom ...

graeme wrote:
> I hope that ISYM is the problem. I just ran the calculation and got the
> following modes:
>
> 1112.247957 cm^{-1} ... 1
> 393.774277 cm^{-1} ... 1
> 122.754647 cm^{-1} ... 1
> 73.095249 cm^{-1} ... 1
> 62.813129 cm^{-1} ... 1
> 179.409466 cm^{-1} ... 0
> 346.386662 cm^{-1 ...

OK thanks.

Yes, it gives images with reasonable bond distances.
So, now I will try IOPT=2 with its default settings and see.

Thanks.

How can we use nebmake.py, there is no information in the online manual? Should we use after nebmake.pl?

Hello,

Is it possible to run neb directly with the optimizer IOPT=2 even if there are high forces at some images where with nebmake.pl a short distance of about 1.2 Ang between two atoms can be found?

Thanks