Dalton forum

Thank you for the comments. Size consistency of the proposed CI (or even RASSCF) approach is a concern. I need polarizabilities over a wide internuclear distance and using rovibrational wavefunctions, I want to compute the relevant transition matrix elements. I have corresponding experimental data f...

Dear all, This question goes in tandem with my previous questions on MCSCF/RASSCF ( http://forum.daltonprogram.org/viewtopic.php?f=9&t=1074 ) on this forum. I am trying to run calculation for simple diatomics using RASSCF aiming to get polarizability. Tests with basis sets have shown slow change in ...

Thank you.

I am trying to rerun a RASSCF calculation with two basis sets for N2. The first calculation goes from HF-> MP2-> RASSCF with the basis cc-pVTZ (this is as suggested on my previous question ( http://forum.daltonprogram.org/viewtopic.php?f=9&t=1074 ). I obtain the output along with the SIRIUS.RST and ...

Thank you.

Thank you for the clarification. I do have another question regarding the RESPONSE calculation. For frequencies crossing the electronic absorption we see negative values for polarizability. Are these the real components. Can we also get the Imaginary components, as shown in the figures in the work :...

Hello all, It appears that the general RESPONSE section has a limit of 30 frequencies which are accepted at a time. If I try to enter more than 30, only the first 30 cases are included in the calculation. Is this behavior as expected. The calculation finishes without any error though. (Full output f...

Hello Prof. Peter,
Thank you for suggestions regarding orbital occupations. Points (1-3) and (5) are clear to me.
For (4), regarding very small occupation numbers I have a question specific to DALTON.

From the manual I do not see specific parameter for defining these Secondary or Virtual orbitals.

My plan was to make a plot of energies vs the 8 symmetries and look for distinctions for RAS1, RAS2 and RAS3 spaces.

Dear Prof. Jensen, I have tried the suggested dal file for calculation and it finishes very fast. I wonder if we can check the orbital energies after the convergence of the MCSCF wavefunction. Similar to the HF orbital energies (Fock eigenvalues) as following , Hartree-Fock orbital energies, symmetr...

Thank you for the insight.

Dear Prof. Taylor and Prof. Jensen, Thank you for the comments. I now understand that the RAS3 space chosen is incorrect. Now running with the suggested RAS3 space. 1. The correlation table for D(inf)h to D2h gives the possible symmetries in D2h and in my case I did not chose RAS3 so that the pairs ...

Hello Dr. Peter,
Thank you for your comments.
The full output file for O2 was uploaded with the original post. It is given here again.

Update 1 : After some testing, does not significantly affect run times. Also it has no effect on the CI coefs.

Update 2: After some testing, in the *.mol files also does not significantly reduce run times.

Thank you for this suggestion. I will definitely check about this. ( Usually we are interested in frequency dependent properties since we have experimental data to compare. )

Dear all, I am running MCSCF calculations for finally obtaining good electronic wavefunctions for later response calculations. Convergence of the electronic wavefuction is slow and I am looking for ways to speed things up. I wonder if reducing the threshold for the integrals maybe a good way. From t...

Thanks for the information.

Dear All, After applying NEVPT2 correction to mcscf wavefunctions, significant reduction in energy is observed. However, the subsequent response calculation falls back to the mcscf wavefunction giving no improvement in the properties. Hence, the question. Can we use the electronic wavenfunction afte...

Dear Prof. Jensen,
Thank you for the reply.
If I understand correctly, I should now include 3s, 3p and possibly 3d orbitals, in the active space for the CI calculation. I guess that should improve the polarizability for CI method.

Hello, I am trying to obtain ground state properties for O2, starting with mcscf (CAS 12) and possibly moving to CI. In this regard, it seems that the wavefunction part of the calculation runs fine, but problems occur for RESPONSE module for CI. ( for mcscf, RESPONSE runs ok and the values of polari...

Hello all, This is a follow up question to this previous question asked in 2013 ( http://forum.daltonprogram.org/viewtopic.php?f=9&t=253&p=1667&hilit=functional+not+fully+implemented%2Ftested+for+QR#p1667 ) For DALTON 2016, which of the DFT functionals are tested for linear, quadratic and cubic resp...

Hello,
You are correct. I confirmed that the program does the vibrational analysis using HF and not the CC wavefunctions. Thanks for the clarification.

Ankit

Hello,
With the **PROPERTIES keyword the .VIBANA analysis works fine as shown in the attached output file ( and the program gave me the hessian as I asked for).

Hello all, I can easily run independent optimization and vibrational analysis (using numerical derivatives) using CCSD using two separate calculations. However, I wonder if it is possible to combine these. Hence, first run optimization, and if the optimization succeeds then do vibrational analysis, ...

Dear Kenneth Ruud,
Thank you very much for the manuscript.