excited keywords

Excited-state SCF parameters

excited.status

Enable excited-state Delta-SCF calculations with the Initial Maximum Overlap Method (IMOM). The target determinant is the occupation of a converged reference calculation given through rho.in with excited.promote applied; at every SCF iteration the occupied orbitals are those with the largest overlap with the target. Supported: self-consistent (vertical excitation) and relaxation calculations with forces, in real space or LCAO, serial or with MPI (without k-point parallelization), with spin.type = ‘collinear’, kpoint.sigma = 0 and a full (unreduced) k-point mesh; symmetries are switched off automatically. During a relaxation the target at each geometry is the excited state converged at the previously evaluated geometry. The reference must have integer occupations (for example kpoint.sampling = ‘fixed’, kpoint.sigma = 0 and kpoint.nocc), save its orbitals (option.saveWavefunction = true in real space, option.saveLCAO = true in LCAO; psi.in, LCAO.coeff, LCAO.DMkcell or Exx.DMinput, if given, must point to the same calculation), use an unreduced k-point mesh (symmetries off unless only the Gamma point is used), and have the same cell, atomic positions, k-point mesh and weights, atom.nvalence and spin.type as the excited run. The run stops with an error for mpi.parak = true with more than one MPI process, sr.method = ‘fmin’, LCAO.usePoleExpansion, eigensolver.bandi(1) ~= 1, or an atom crossing a cell face in an LCAO relaxation with k-points other than Gamma. In LCAO, mixing.type = ‘density-matrix’ is supported; unless LCAO.coeff, LCAO.DMkcell or Exx.DMinput is given, the mixer starts from the density matrix of the reference calculation. Hybrid functionals (LCAO) are supported for self-consistent runs only, since RESCU has no exact-exchange forces; use mixing.type = ‘density-matrix’ (the default for hybrid functionals) and give the Exx settings of the ground-state run used for the energy difference (Exx keywords missing from the input are read from a hybrid reference, as far as its .mat file holds them, and otherwise take their defaults). DFT+U is supported in LCAO for self-consistent runs only, since RESCU does not compute the Hubbard contribution to the forces: a DFT+U relaxation stops with an error and force.status is set to false (with a warning if the input sets it). Use mixing.type = ‘density-matrix’ (not the default; a warning is printed otherwise) and give the same element.CoulombEnergyU as the ground-state run used for the energy difference.

type: scalar

default: false

allowed: true,false

example: excited.status = true

excited.method

Excited-state occupation selector. ‘imom’ is the only method: at every SCF iteration it occupies the orbitals with the largest overlap with a fixed target determinant (see excited.status).

type: string

default: 'imom'

allowed: 'imom'

example: excited.method = 'imom'

excited.promote

Promotions that define the excited state, one row per electron moved: [k_hole, band_hole, spin_hole, k_elec, band_elec, spin_elec]. Indices are 1-based: k is the k-point index in the full mesh, band the band index in the energy order of the rho.in reference, and spin the collinear spin channel (1 or 2). The rows are applied in order to the reference occupations; the result must have occupations 0 or 1 and the same number of electrons (for a single row: the hole occupied and the target band empty in the reference). Required when excited.status = true.

type: array

size: [inf,6]

example: excited.promote = [1,8,1,1,9,1]

excited.tieTol

Overlap-score tolerance used to detect deterministic IMOM ties. Tied scores are ordered by lower Kohn-Sham energy and then by lower band index.

type: scalar

default: 1e-08

example: excited.tieTol = 1e-8