QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: leslie on June 7, 2011, 08:50

Title: how to define confinement orbital as hard_well in ATK basis set ?
Post by: leslie on June 7, 2011, 08:50

Hi friends,

In Siesta, the basis set (atomic orbitals) is generated using a confinement potential. The default for this confiment potential is Sankey Hard Well (V=0 for r<a and V=infinity for r>a) in Siesta. An alternative (and better) confinement potential is soft-confinement potential V(r)=Voexp[-(rc-ri)/(r-ri)]/(rc-r).

In ATK, however, the only choice is soft-confinement potential, which is defined in the class ConfinedOrbital
 ConfinedOrbital(
principal_quantum_number,
angular_momentum,
radial_cutoff_radius,
confinement_start_radius,
additional_charge,
confinement_strength,
radial_step_size
)

Anyone knows what to do if I want to use the Sankey Hard Well potential instead of soft-confinement potential with ATK?

Title: Re: how to define confinement orbital as hard_well in ATK basis set ?
Post by: Nordland on June 7, 2011, 12:21

If you set the confinement start radius and the radial cutoff radius very close one another, and increase the confinement strength dramatic, you will effectively have
a Sankey Hard Well potential.

Title: Re: how to define confinement orbital as hard_well in ATK basis set ?
Post by: zhangguangping on September 18, 2018, 14:28

Quote from: Nordland on June  7, 2011, 12:21

If you set the confinement start radius and the radial cutoff radius very close one another, and increase the confinement strength dramatic, you will effectively have
a Sankey Hard Well potential.

Dear Nordland,

Another question on this topic is that how can I tune the radial_cutoff_radius to a very small value? When I tried to set is to a small value, such as 0.5 Bohr, ATK will abort.

With best regards,

/Guang-Ping Zhang