ASD orbital optimization

Description

Active space decomposition with orbital optimization is implemented. Set "title" = "asd_orbopt" to start the input section. The two fragments of the molecule can be covalently linked, but the bridging orbitals cannot be active. Orbital rotations between active subspaces are included to partition the total active space into subspaces. The two active subspaces should be well separated. The calculation starts with dimer construction which is slightly different from that in Dimer ASD.

Dimer Construction

• Description
• Keywords
• Prerequisite

Keywords

Required Keywords

algorithm

Description: ‘bfgs’ orbital optimization algorithm is implemented.

Datatype: string

Value: bfgs

maxiter

Description: Maximum number of orbital optimization iterations.

Datatype: int

Default: 50

asd

Description: asd block specifies asd options.

Recommendation: See Dimer ASD for details.

gradient_thresh

Description: Threshold for calculating gradient.

Datatype: double

Default: 0.0001

Recommendation: Use default.

rotation_thresh

Description: Threshold for orbital rotation.

Datatype: double

Default: 0.0001

Recommendation: Use default.

energy_thresh

Description: Convergence threshold for calculating energy.

Datatype: double

Default: \(1.0\times 10^{-6}\)

Recommendation: Use default.

semi-canonicalize

Description: Whether to semi-canonicalize localized orbitals.

Datatype: bool

Default: false

Reference

Description of Reference	Reference
ASD orbital optimization	I. Kim, S. M. Parker, and T. Shiozaki, J. Chem. Theory Comput. 11, 3636 (2015).