Use pyxaid2 to run the specific calculations in step2

[Wei Li]

Hi Everyone,

if you have just accessed to Pyxaid2 program, you may be interested in what type of calculations can the Pyxaid2 program perform.

The Pyxaid2 can do the following four types of calculations:

1. non-relativistic and non-spin polarized calculation
2. non-relativistic and spin-polarized calculation
3. relativistic calculation
4. do the spin-polarized and relativistic calculations at the same time

The best way to get familiar with these is to try the examples at here. The switch of the different calculations is controlled by the nac_method parameter. 

nac_method = 0, 

this option will start the non-relativistic and non-spin polarized calculation. Noted that the non-relativistic pp should be used. The x0.scf.in x0.exp.in files need be presented in the directory.

nac_method=1,

this option will start the non-relativistic and spin-polarized calculation. Same as nac_method=0 option, the non-relativistic pp and x0.scf.in x0.exp.in files are needed as well. The difference is spin-polarized calculation need the nspin=2. The resulted KS state from spin-polarized calculation is called diabatic state, which means the spin-up (alpha) and spin-down (beta) states are in pure state. Different spin were not coupled.  

nac_method=2,

this option will start the relativistic calculation. We want to include the spin-orbit coupling effect. The full relativistic pp for the heavy elements and x1.scf.in x1.exp.in files are needed. In addition, the parameters for SOC calculation need be set in x1.scf.in file. The resulted KS state from the relativistic calculation is called adiabatic state. The alpha and beta states were mixed with each other.

nac_method=3,

this option will start the spin-polarized calculation and relativistic calculation at the same time. The relativistic and non-relativistic pp, x0.scf.in x1.scf.in x0.exp.in x1.exp.in files need be presented in the directory. This option will calculate the coupling between diabatic states, and also adiabatic states. In addition, the alpha and beta electrons were coupled since the SOC effect. This is achieved from the adiabatic/diabatic projection, then calculate the coupling between diabatic state after projection. This is very useful to investigate the intersystem crossing (ISC) process. The manuscript for describing the theory is under preparation. Noted that in this case a large number of adiabatic states need be included.

In the next post I will show you how to run the NA-MD in step3 with pyxaid2.

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[Kamal Dhungana]

Dear Wei,

The procedures for NA-MD calculation in step 3 are different for pyxaid and pyxaid2. When are you going to show the step 3 calculation for pyxaid2. We are waiting for it.

Best Regards,

Kamal 

[Wei Li]

Hi Kamal, 

Some of the functionalities for Pyxaid2 is still under development, but hopefully, it would be ready soon. We are working on step3 at this moment. I will let you all know once it is ready to be used. 

Sorry for the inconvenience. 

Wei

[Kamal Dhungana]

Dear Wei,

 The calculation of Hprime part in step 2 is permanently removed in PYXAID2?

Regards,

Kamal  

[Wei Li]

Hi Kamal,

yes, it was removed. But perhaps we will add it back soon, just need to calculate the transition dipole moment in x,y,z direction.

Wei

[Kamal Dhungana]

Dear Wei,

Thank you very much for your kind response.

Regards,

Kamal

[Kamal Dhungana]

Dear Wei,

I tried to perform my 2nd step calculation with k points more than (1 1 1), but I am not successful. For k = (1 1 1), it computes all the Ham elements. For higher k points, it neither computes Ham elements and nor gives any error massage. In all your examples (provided with pyxaid2), you always consider k-point (1 1 1). Did you try k-point higher than (1 1 1) with pyxaid2?  

Best Regards,

Kamal

[Wei Li]

Hi Kamal,

Currently, the multiple kpoints for NAC with SOC calculation in Pyxaid2 is not available. However, the multiple kpoints for NAC without SOC does implement here, please see the 0- example.

Wei