QUADRATIC_PSEUDOSPECTRUM
References: Cerjan2023
Joint position/energy localization analysis for GPW/GAPW systems. Uses full AO H, S and analytic first moments or periodic trigonometric coordinates. No occupied-state projection and no topology index. Residuals concern finite-basis projected operators, not exact real-space variances. [Edit on GitHub]
Subsections
Keywords
Keyword descriptions
SECTION_PARAMETERS
Type: logical
Default: F
Lone keyword: T
Description: Activate post-SCF quadratic pseudospectrum analysis. [Edit on GitHub]
ENERGY
Type: real[ ]
Default: 0.00000000E+000 [hartree]
Description: Absolute query energies; every POSITION/ENERGY/KAPPA combination is evaluated. [Edit on GitHub]
EPS_EIGEN
Type: real
Default: 1.00000000E-008
Description: Convergence criterion: S-inverse residual norm <= EPS_EIGEN times max(1,abs(eigenvalue)), with eigenvalues in atomic units of energy squared. [Edit on GitHub]
EPS_METRIC
Type: real
Default: 1.00000000E-010
Description: Minimum AO metric eigenvalue ratio. Ill-conditioned directions are rejected, not silently discarded. [Edit on GitHub]
FORMULATION
Type: enum
Default: FINITE
Description: FINITE uses Cartesian first moments for isolated systems. PERIODIC uses cos(G.r)/sin(G.r) on a Born-von-Karman torus in the periodic CELL directions only. Open directions are not localized by PERIODIC. TRANSLATION uses analytic translated Gaussian overlaps, with continuum translation norms and explicit AO leakage. Periodic TRANSLATION uses periodized AOs on the full MP_GRID torus; finite translations need no KPOINTS. ENERGY still refers to the projected AO Hamiltonian; no boundary suppression is applied. [Edit on GitHub]
Valid values:
FINITEPERIODICTRANSLATION
KAPPA
Type: real[ ]
Default: 1.00000000E-002 [bohr^-1*hartree]
Description: Positive energy/length scales for Cartesian residuals (FINITE) or periodic chord residuals divided by reciprocal-vector norms (PERIODIC). Check basis, system-size and KAPPA convergence. [Edit on GitHub]
MAX_AO
Type: integer
Default: 512
Description: Scalar AO safety limit for the dense solver, including all periodic torus cells. Increase deliberately for large systems. SOC doubles the operator dimension; DENSE uses quadratic memory. [Edit on GitHub]
MP_GRID
Type: integer[3]
Default: 1 1 1
Description: Full Gamma-centered mesh for PERIODIC or periodic TRANSLATION, independent of SCF symmetry reduction. Equivalent to a Gamma supercell at the frozen SCF potential. Nonperiodic directions must be one; MAX_AO bounds the entire torus. [Edit on GitHub]
NSTATES
Type: integer
Default: 1
Description: Number of lowest quadratic-operator eigenstates, S-normalized. [Edit on GitHub]
POSITION
Type: real[3]
Default: 0.00000000E+000 0.00000000E+000 0.00000000E+000 [bohr]
Repeatable: yes
Description: Query position in the SUBSYS/COORD frame. Repeat for spatial scans. [Edit on GitHub]
SOC
Type: logical
Default: F
Description: Add GTH SOC to the restricted converged AO Hamiltonian. Requires SOC pseudopotentials; not a self-consistent noncollinear calculation. [Edit on GitHub]
SOLVER
Type: enum
Default: DENSE
Description: Dense LAPACK reference calculation in the AO overlap metric. [Edit on GitHub]
Valid values:
DENSE
SPIN_CHANNEL
Type: integer
Default: 1
Description: Collinear scalar spin channel. SOC requires a restricted SCF and channel 1. [Edit on GitHub]
TRANSLATION_SCALE
Type: real[ ]
Default: 1.00000000E+000 [hartree]
Description: Positive energy scales for dimensionless full translation residuals. Every WAVE_VECTOR/ENERGY/TRANSLATION_SCALE combination is evaluated. Only with FORMULATION TRANSLATION, replacing the energy/length-valued KAPPA. [Edit on GitHub]
TRANSLATION_VECTOR
Type: real[3]
Default: [bohr]
Repeatable: yes
Description: Cartesian vector a in the input coordinate frame, for U(a) psi(r) = psi(r+a). Repeat for each equally weighted translation. Only with FORMULATION TRANSLATION. Choose directions and lengths deliberately; this defines a momentum-resolution metric. [Edit on GitHub]
WAVE_VECTOR
Type: real[3]
Default: 0.00000000E+000 0.00000000E+000 0.00000000E+000 [bohr^-1]
Repeatable: yes
Description: Cartesian momentum query k in the input frame; phase is exp(i k.a), without an additional 2*pi. Repeat for scans. Only with FORMULATION TRANSLATION. [Edit on GitHub]