QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: Roc on December 27, 2008, 09:52

Title: some questions about MPSH
Post by: Roc on December 27, 2008, 09:52
Dear everyone,

In this tutorial analyzing the Li-H2-Li two-probe system, a part of one script is that,

# Calculate HOMO and LUMO eigenstates for the H atoms in the two-probe system
eigenstates = calculateProjectedHamiltonianEigenstates(
    scf, projection_atoms = [3,4],
    quantum_numbers = [0,1]
    )


For other two-probe systems, how to decide the "Quantum Numbers " in VNL when I calculate Projected Hamiltonian eigenstates to obtain the HOMO、LUMO、HOMO-N and LUMO+N 

Thanks!
Title: Re: some questions about MPSH
Post by: Nordland on December 27, 2008, 19:11
The way I would do it, is not automated, but I will use the function calculateProjectedHamiltonianEnergySpectrum - you can see the documentation here. (http://www.quantumwise.com/documents/manuals/ATK-2008.10/ref.calculateprojectedhamiltonianenergyspectrum.html)

From that you will find the energy spectrum, and you can identify the quantum number for the homo-lumo from the the energies since zero is the fermi energy.
You will the find the HOMO as the first quantum number below zero ( in order words the last negative one) and the LUMO as the first above zero (in order words the first positive energy). Then you can define N as you want since you will have the quantum numbers for both the HOMO and LUMO.

But it is only a suggestion.
Title: Re: some questions about MPSH
Post by: Roc on December 28, 2008, 01:46
Thank you very much, Nordland ! I see.  :)