Line data Source code
1 : !--------------------------------------------------------------------------------------------------!
2 : ! CP2K: A general program to perform molecular dynamics simulations !
3 : ! Copyright 2000-2024 CP2K developers group <https://cp2k.org> !
4 : ! !
5 : ! SPDX-License-Identifier: GPL-2.0-or-later !
6 : !--------------------------------------------------------------------------------------------------!
7 :
8 : ! **************************************************************************************************
9 : !> \brief Set occupation of molecular orbitals
10 : !> \par History
11 : !> - set_mo_occupation subroutines moved from qs_mo_types (11.12.2014 MI)
12 : !> \author MI
13 : ! **************************************************************************************************
14 :
15 : MODULE qs_mo_occupation
16 :
17 : USE cp_log_handling, ONLY: cp_to_string
18 : USE fermi_utils, ONLY: FermiFixed,&
19 : FermiFixedDeriv
20 : USE input_constants, ONLY: smear_energy_window,&
21 : smear_fermi_dirac,&
22 : smear_list
23 : USE kahan_sum, ONLY: accurate_sum
24 : USE kinds, ONLY: dp
25 : USE qs_mo_types, ONLY: get_mo_set,&
26 : has_uniform_occupation,&
27 : mo_set_type,&
28 : set_mo_set
29 : USE scf_control_types, ONLY: smear_type
30 : USE util, ONLY: sort
31 : USE xas_env_types, ONLY: get_xas_env,&
32 : xas_environment_type
33 : #include "./base/base_uses.f90"
34 :
35 : IMPLICIT NONE
36 :
37 : PRIVATE
38 :
39 : CHARACTER(len=*), PARAMETER, PRIVATE :: moduleN = 'qs_mo_occupation'
40 :
41 : PUBLIC :: set_mo_occupation
42 :
43 : INTERFACE set_mo_occupation
44 : MODULE PROCEDURE set_mo_occupation_1, set_mo_occupation_2
45 : END INTERFACE
46 :
47 : CONTAINS
48 :
49 : ! **************************************************************************************************
50 : !> \brief Occupation for smeared spin polarized electronic structures
51 : !> with relaxed multiplicity
52 : !>
53 : !> \param mo_array ...
54 : !> \param smear ...
55 : !> \date 10.03.2011 (MI)
56 : !> \author MI
57 : !> \version 1.0
58 : ! **************************************************************************************************
59 46 : SUBROUTINE set_mo_occupation_3(mo_array, smear)
60 :
61 : TYPE(mo_set_type), DIMENSION(2), INTENT(INOUT) :: mo_array
62 : TYPE(smear_type), POINTER :: smear
63 :
64 : CHARACTER(LEN=*), PARAMETER :: routineN = 'set_mo_occupation_3'
65 :
66 : INTEGER :: all_nmo, handle, homo_a, homo_b, i, &
67 : lfomo_a, lfomo_b, nmo_a, nmo_b, &
68 : xas_estate
69 46 : INTEGER, ALLOCATABLE, DIMENSION(:) :: all_index
70 : LOGICAL :: is_large
71 : REAL(KIND=dp) :: all_nelec, kTS, mu, nelec_a, nelec_b, &
72 : occ_estate
73 : REAL(KIND=dp), ALLOCATABLE, DIMENSION(:) :: all_eigval, all_occ
74 46 : REAL(KIND=dp), DIMENSION(:), POINTER :: eigval_a, eigval_b, occ_a, occ_b
75 :
76 46 : CALL timeset(routineN, handle)
77 :
78 46 : NULLIFY (eigval_a, eigval_b, occ_a, occ_b)
79 : CALL get_mo_set(mo_set=mo_array(1), nmo=nmo_a, eigenvalues=eigval_a, &
80 46 : occupation_numbers=occ_a)
81 : CALL get_mo_set(mo_set=mo_array(2), nmo=nmo_b, eigenvalues=eigval_b, &
82 46 : occupation_numbers=occ_b)
83 46 : all_nmo = nmo_a + nmo_b
84 138 : ALLOCATE (all_eigval(all_nmo))
85 92 : ALLOCATE (all_occ(all_nmo))
86 138 : ALLOCATE (all_index(all_nmo))
87 :
88 1264 : all_eigval(1:nmo_a) = eigval_a(1:nmo_a)
89 1264 : all_eigval(nmo_a + 1:all_nmo) = eigval_b(1:nmo_b)
90 :
91 46 : CALL sort(all_eigval, all_nmo, all_index)
92 :
93 46 : xas_estate = -1
94 46 : occ_estate = 0.0_dp
95 :
96 : nelec_a = 0.0_dp
97 : nelec_b = 0.0_dp
98 : all_nelec = 0.0_dp
99 46 : nelec_a = accurate_sum(occ_a(:))
100 46 : nelec_b = accurate_sum(occ_b(:))
101 46 : all_nelec = nelec_a + nelec_b
102 :
103 2482 : DO i = 1, all_nmo
104 2482 : IF (all_index(i) <= nmo_a) THEN
105 1218 : all_occ(i) = occ_a(all_index(i))
106 : ELSE
107 1218 : all_occ(i) = occ_b(all_index(i) - nmo_a)
108 : END IF
109 : END DO
110 :
111 : CALL FermiFixed(all_occ, mu, kTS, all_eigval, all_nelec, &
112 46 : smear%electronic_temperature, 1._dp, xas_estate, occ_estate)
113 :
114 2528 : is_large = ABS(MAXVAL(all_occ) - 1.0_dp) > smear%eps_fermi_dirac
115 : ! this is not a real problem, but the temperature might be a bit large
116 46 : CPWARN_IF(is_large, "Fermi-Dirac smearing includes the first MO")
117 :
118 2528 : is_large = ABS(MINVAL(all_occ)) > smear%eps_fermi_dirac
119 46 : IF (is_large) &
120 : CALL cp_warn(__LOCATION__, &
121 : "Fermi-Dirac smearing includes the last MO => "// &
122 0 : "Add more MOs for proper smearing.")
123 :
124 : ! check that the total electron count is accurate
125 46 : is_large = (ABS(all_nelec - accurate_sum(all_occ(:))) > smear%eps_fermi_dirac*all_nelec)
126 46 : CPWARN_IF(is_large, "Total number of electrons is not accurate")
127 :
128 2482 : DO i = 1, all_nmo
129 2482 : IF (all_index(i) <= nmo_a) THEN
130 1218 : occ_a(all_index(i)) = all_occ(i)
131 1218 : eigval_a(all_index(i)) = all_eigval(i)
132 : ELSE
133 1218 : occ_b(all_index(i) - nmo_a) = all_occ(i)
134 1218 : eigval_b(all_index(i) - nmo_a) = all_eigval(i)
135 : END IF
136 : END DO
137 :
138 46 : nelec_a = accurate_sum(occ_a(:))
139 46 : nelec_b = accurate_sum(occ_b(:))
140 :
141 530 : DO i = 1, nmo_a
142 530 : IF (occ_a(i) < 1.0_dp) THEN
143 46 : lfomo_a = i
144 46 : EXIT
145 : END IF
146 : END DO
147 528 : DO i = 1, nmo_b
148 528 : IF (occ_b(i) < 1.0_dp) THEN
149 46 : lfomo_b = i
150 46 : EXIT
151 : END IF
152 : END DO
153 46 : homo_a = lfomo_a - 1
154 488 : DO i = nmo_a, lfomo_a, -1
155 488 : IF (occ_a(i) > smear%eps_fermi_dirac) THEN
156 46 : homo_a = i
157 46 : EXIT
158 : END IF
159 : END DO
160 46 : homo_b = lfomo_b - 1
161 488 : DO i = nmo_b, lfomo_b, -1
162 488 : IF (occ_b(i) > smear%eps_fermi_dirac) THEN
163 46 : homo_b = i
164 46 : EXIT
165 : END IF
166 : END DO
167 :
168 : CALL set_mo_set(mo_set=mo_array(1), kTS=kTS/2.0_dp, mu=mu, n_el_f=nelec_a, &
169 46 : lfomo=lfomo_a, homo=homo_a, uniform_occupation=.FALSE.)
170 : CALL set_mo_set(mo_set=mo_array(2), kTS=kTS/2.0_dp, mu=mu, n_el_f=nelec_b, &
171 46 : lfomo=lfomo_b, homo=homo_b, uniform_occupation=.FALSE.)
172 :
173 46 : CALL timestop(handle)
174 :
175 92 : END SUBROUTINE set_mo_occupation_3
176 :
177 : ! **************************************************************************************************
178 : !> \brief Prepare an occupation of alpha and beta MOs following an Aufbau
179 : !> principle, i.e. allowing a change in multiplicity.
180 : !> \param mo_array ...
181 : !> \param smear ...
182 : !> \param eval_deriv ...
183 : !> \param tot_zeff_corr ...
184 : !> \date 25.01.2010 (MK)
185 : !> \par History
186 : !> 10.2019 Added functionality to adjust mo occupation if the core
187 : !> charges are changed via CORE_CORRECTION during surface dipole
188 : !> calculation. Total number of electrons matches the total core
189 : !> charges if tot_zeff_corr is non-zero. Not yet implemented for
190 : !> OT type method. [Soumya Ghosh]
191 : !> \author Matthias Krack (MK)
192 : !> \version 1.0
193 : ! **************************************************************************************************
194 81577 : SUBROUTINE set_mo_occupation_2(mo_array, smear, eval_deriv, tot_zeff_corr)
195 :
196 : TYPE(mo_set_type), DIMENSION(:), INTENT(INOUT) :: mo_array
197 : TYPE(smear_type), POINTER :: smear
198 : REAL(KIND=dp), DIMENSION(:), OPTIONAL, POINTER :: eval_deriv
199 : REAL(KIND=dp), OPTIONAL :: tot_zeff_corr
200 :
201 : CHARACTER(LEN=*), PARAMETER :: routineN = 'set_mo_occupation_2'
202 :
203 : INTEGER :: handle, i, lumo_a, lumo_b, &
204 : multiplicity_new, multiplicity_old, &
205 : nelec
206 : REAL(KIND=dp) :: nelec_f, threshold
207 81577 : REAL(KIND=dp), DIMENSION(:), POINTER :: eigval_a, eigval_b
208 :
209 81577 : CALL timeset(routineN, handle)
210 :
211 : ! Fall back for the case that we have only one MO set
212 81577 : IF (SIZE(mo_array) == 1) THEN
213 71587 : IF (PRESENT(eval_deriv)) THEN
214 : ! Change of MO occupancy to account for CORE_CORRECTION is not yet implemented
215 0 : CALL set_mo_occupation_1(mo_array(1), smear=smear, eval_deriv=eval_deriv)
216 : ELSE
217 71587 : IF (PRESENT(tot_zeff_corr)) THEN
218 20 : CALL set_mo_occupation_1(mo_array(1), smear=smear, tot_zeff_corr=tot_zeff_corr)
219 : ELSE
220 71567 : CALL set_mo_occupation_1(mo_array(1), smear=smear)
221 : END IF
222 : END IF
223 71587 : CALL timestop(handle)
224 : RETURN
225 : END IF
226 :
227 9990 : IF (smear%do_smear) THEN
228 1416 : IF (smear%fixed_mag_mom < 0.0_dp) THEN
229 46 : IF (PRESENT(tot_zeff_corr)) THEN
230 : CALL cp_warn(__LOCATION__, &
231 : "CORE_CORRECTION /= 0.0 might cause the cell to charge up "// &
232 : "that will lead to application of different background "// &
233 : "correction compared to the reference system. "// &
234 : "Use FIXED_MAGNETIC_MOMENT >= 0.0 if using SMEAR keyword "// &
235 0 : "to correct the electron density")
236 : END IF
237 46 : IF (smear%fixed_mag_mom /= -1.0_dp) THEN
238 46 : CPASSERT(.NOT. (PRESENT(eval_deriv)))
239 46 : CALL set_mo_occupation_3(mo_array, smear=smear)
240 46 : CALL timestop(handle)
241 46 : RETURN
242 : END IF
243 : ELSE
244 1370 : nelec_f = mo_array(1)%n_el_f + mo_array(2)%n_el_f
245 1370 : IF (ABS((mo_array(1)%n_el_f - mo_array(2)%n_el_f) - smear%fixed_mag_mom) > smear%eps_fermi_dirac*nelec_f) THEN
246 2 : mo_array(1)%n_el_f = nelec_f/2.0_dp + smear%fixed_mag_mom/2.0_dp
247 2 : mo_array(2)%n_el_f = nelec_f/2.0_dp - smear%fixed_mag_mom/2.0_dp
248 : END IF
249 1370 : CPASSERT(.NOT. (PRESENT(eval_deriv)))
250 1370 : IF (PRESENT(tot_zeff_corr)) THEN
251 20 : CALL set_mo_occupation_1(mo_array(1), smear=smear, tot_zeff_corr=tot_zeff_corr)
252 20 : CALL set_mo_occupation_1(mo_array(2), smear=smear, tot_zeff_corr=tot_zeff_corr)
253 : ELSE
254 1350 : CALL set_mo_occupation_1(mo_array(1), smear=smear)
255 1350 : CALL set_mo_occupation_1(mo_array(2), smear=smear)
256 : END IF
257 : END IF
258 : END IF
259 :
260 9944 : IF (.NOT. ((mo_array(1)%flexible_electron_count > 0.0_dp) .AND. &
261 : (mo_array(2)%flexible_electron_count > 0.0_dp))) THEN
262 9778 : IF (PRESENT(eval_deriv)) THEN
263 0 : CALL set_mo_occupation_1(mo_array(1), smear=smear, eval_deriv=eval_deriv)
264 0 : CALL set_mo_occupation_1(mo_array(2), smear=smear, eval_deriv=eval_deriv)
265 : ELSE
266 9778 : IF (PRESENT(tot_zeff_corr)) THEN
267 20 : CALL set_mo_occupation_1(mo_array(1), smear=smear, tot_zeff_corr=tot_zeff_corr)
268 20 : CALL set_mo_occupation_1(mo_array(2), smear=smear, tot_zeff_corr=tot_zeff_corr)
269 : ELSE
270 9758 : CALL set_mo_occupation_1(mo_array(1), smear=smear)
271 9758 : CALL set_mo_occupation_1(mo_array(2), smear=smear)
272 : END IF
273 : END IF
274 9778 : CALL timestop(handle)
275 9778 : RETURN
276 : END IF
277 :
278 166 : nelec = mo_array(1)%nelectron + mo_array(2)%nelectron
279 :
280 166 : multiplicity_old = mo_array(1)%nelectron - mo_array(2)%nelectron + 1
281 :
282 166 : IF (mo_array(1)%nelectron >= mo_array(1)%nmo) &
283 : CALL cp_warn(__LOCATION__, &
284 : "All alpha MOs are occupied. Add more alpha MOs to "// &
285 0 : "allow for a higher multiplicity")
286 166 : IF ((mo_array(2)%nelectron >= mo_array(2)%nmo) .AND. (mo_array(2)%nelectron /= mo_array(1)%nelectron)) &
287 : CALL cp_warn(__LOCATION__, "All beta MOs are occupied. Add more beta MOs to "// &
288 0 : "allow for a lower multiplicity")
289 :
290 166 : eigval_a => mo_array(1)%eigenvalues
291 166 : eigval_b => mo_array(2)%eigenvalues
292 :
293 166 : lumo_a = 1
294 166 : lumo_b = 1
295 :
296 : ! Apply Aufbau principle
297 2046 : DO i = 1, nelec
298 : ! Threshold is needed to ensure a preference for alpha occupation in the case
299 : ! of degeneracy
300 1880 : threshold = MAX(mo_array(1)%flexible_electron_count, mo_array(2)%flexible_electron_count)
301 1880 : IF ((eigval_a(lumo_a) - threshold) < eigval_b(lumo_b)) THEN
302 1072 : lumo_a = lumo_a + 1
303 : ELSE
304 808 : lumo_b = lumo_b + 1
305 : END IF
306 1880 : IF (lumo_a > mo_array(1)%nmo) THEN
307 0 : IF (i /= nelec) &
308 : CALL cp_warn(__LOCATION__, &
309 : "All alpha MOs are occupied. Add more alpha MOs to "// &
310 0 : "allow for a higher multiplicity")
311 0 : IF (i < nelec) THEN
312 0 : lumo_a = lumo_a - 1
313 0 : lumo_b = lumo_b + 1
314 : END IF
315 : END IF
316 2046 : IF (lumo_b > mo_array(2)%nmo) THEN
317 34 : IF (lumo_b < lumo_a) &
318 : CALL cp_warn(__LOCATION__, &
319 : "All beta MOs are occupied. Add more beta MOs to "// &
320 0 : "allow for a lower multiplicity")
321 34 : IF (i < nelec) THEN
322 6 : lumo_a = lumo_a + 1
323 6 : lumo_b = lumo_b - 1
324 : END IF
325 : END IF
326 : END DO
327 :
328 166 : mo_array(1)%homo = lumo_a - 1
329 166 : mo_array(2)%homo = lumo_b - 1
330 :
331 166 : IF (mo_array(2)%homo > mo_array(1)%homo) THEN
332 : CALL cp_warn(__LOCATION__, &
333 : "More beta ("// &
334 : TRIM(ADJUSTL(cp_to_string(mo_array(2)%homo)))// &
335 : ") than alpha ("// &
336 : TRIM(ADJUSTL(cp_to_string(mo_array(1)%homo)))// &
337 0 : ") MOs are occupied. Resorting to low spin state")
338 0 : mo_array(1)%homo = nelec/2 + MODULO(nelec, 2)
339 0 : mo_array(2)%homo = nelec/2
340 : END IF
341 :
342 166 : mo_array(1)%nelectron = mo_array(1)%homo
343 166 : mo_array(2)%nelectron = mo_array(2)%homo
344 166 : multiplicity_new = mo_array(1)%nelectron - mo_array(2)%nelectron + 1
345 :
346 166 : IF (multiplicity_new /= multiplicity_old) &
347 : CALL cp_warn(__LOCATION__, &
348 : "Multiplicity changed from "// &
349 : TRIM(ADJUSTL(cp_to_string(multiplicity_old)))//" to "// &
350 8 : TRIM(ADJUSTL(cp_to_string(multiplicity_new))))
351 :
352 166 : IF (PRESENT(eval_deriv)) THEN
353 0 : CALL set_mo_occupation_1(mo_array(1), smear=smear, eval_deriv=eval_deriv)
354 0 : CALL set_mo_occupation_1(mo_array(2), smear=smear, eval_deriv=eval_deriv)
355 : ELSE
356 166 : IF (PRESENT(tot_zeff_corr)) THEN
357 0 : CALL set_mo_occupation_1(mo_array(1), smear=smear, tot_zeff_corr=tot_zeff_corr)
358 0 : CALL set_mo_occupation_1(mo_array(2), smear=smear, tot_zeff_corr=tot_zeff_corr)
359 : ELSE
360 166 : CALL set_mo_occupation_1(mo_array(1), smear=smear)
361 166 : CALL set_mo_occupation_1(mo_array(2), smear=smear)
362 : END IF
363 : END IF
364 :
365 166 : CALL timestop(handle)
366 :
367 81577 : END SUBROUTINE set_mo_occupation_2
368 :
369 : ! **************************************************************************************************
370 : !> \brief Smearing of the MO occupation with all kind of occupation numbers
371 : !> \param mo_set MO dataset structure
372 : !> \param smear optional smearing information
373 : !> \param eval_deriv on entry the derivative of the KS energy wrt to the occupation number
374 : !> on exit the derivative of the full free energy (i.e. KS and entropy) wrt to the eigenvalue
375 : !> \param xas_env ...
376 : !> \param tot_zeff_corr ...
377 : !> \date 17.04.2002 (v1.0), 26.08.2008 (v1.1)
378 : !> \par History
379 : !> 10.2019 Added functionality to adjust mo occupation if the core
380 : !> charges are changed via CORE_CORRECTION during surface dipole
381 : !> calculation. Total number of electrons matches the total core
382 : !> charges if tot_zeff_corr is non-zero. Not yet implemented for
383 : !> OT type method. [Soumya Ghosh]
384 : !> \author Matthias Krack
385 : !> \version 1.1
386 : ! **************************************************************************************************
387 194384 : SUBROUTINE set_mo_occupation_1(mo_set, smear, eval_deriv, xas_env, tot_zeff_corr)
388 :
389 : TYPE(mo_set_type), INTENT(INOUT) :: mo_set
390 : TYPE(smear_type), OPTIONAL, POINTER :: smear
391 : REAL(KIND=dp), DIMENSION(:), OPTIONAL, POINTER :: eval_deriv
392 : TYPE(xas_environment_type), OPTIONAL, POINTER :: xas_env
393 : REAL(KIND=dp), OPTIONAL :: tot_zeff_corr
394 :
395 : CHARACTER(LEN=*), PARAMETER :: routineN = 'set_mo_occupation_1'
396 :
397 : INTEGER :: handle, i_first, imo, ir, irmo, nmo, &
398 : nomo, xas_estate
399 : LOGICAL :: equal_size, is_large
400 : REAL(KIND=dp) :: delectron, e1, e2, edelta, edist, &
401 : el_count, lengthscale, nelec, &
402 : occ_estate, total_zeff_corr, &
403 : xas_nelectron
404 194384 : REAL(KIND=dp), ALLOCATABLE, DIMENSION(:, :) :: dfde
405 :
406 194384 : CALL timeset(routineN, handle)
407 :
408 194384 : CPASSERT(ASSOCIATED(mo_set%eigenvalues))
409 194384 : CPASSERT(ASSOCIATED(mo_set%occupation_numbers))
410 2005084 : mo_set%occupation_numbers(:) = 0.0_dp
411 :
412 : ! Quick return, if no electrons are available
413 194384 : IF (mo_set%nelectron == 0) THEN
414 1580 : CALL timestop(handle)
415 1580 : RETURN
416 : END IF
417 :
418 192804 : xas_estate = -1
419 192804 : occ_estate = 0.0_dp
420 192804 : IF (PRESENT(xas_env)) THEN
421 786 : CALL get_xas_env(xas_env=xas_env, xas_nelectron=xas_nelectron, occ_estate=occ_estate, xas_estate=xas_estate)
422 786 : nomo = CEILING(xas_nelectron + 1.0 - occ_estate - EPSILON(0.0_dp))
423 :
424 7802 : mo_set%occupation_numbers(1:nomo) = mo_set%maxocc
425 786 : IF (xas_estate > 0) mo_set%occupation_numbers(xas_estate) = occ_estate
426 7802 : el_count = SUM(mo_set%occupation_numbers(1:nomo))
427 786 : IF (el_count > xas_nelectron) &
428 98 : mo_set%occupation_numbers(nomo) = mo_set%occupation_numbers(nomo) - (el_count - xas_nelectron)
429 7802 : el_count = SUM(mo_set%occupation_numbers(1:nomo))
430 786 : is_large = ABS(el_count - xas_nelectron) > xas_nelectron*EPSILON(el_count)
431 786 : CPASSERT(.NOT. is_large)
432 : ELSE
433 192018 : IF (MODULO(mo_set%nelectron, INT(mo_set%maxocc)) == 0) THEN
434 190976 : nomo = NINT(mo_set%nelectron/mo_set%maxocc)
435 : ! Initialize MO occupations
436 1840864 : mo_set%occupation_numbers(1:nomo) = mo_set%maxocc
437 : ELSE
438 1042 : nomo = INT(mo_set%nelectron/mo_set%maxocc) + 1
439 : ! Initialize MO occupations
440 6648 : mo_set%occupation_numbers(1:nomo - 1) = mo_set%maxocc
441 1042 : mo_set%occupation_numbers(nomo) = mo_set%nelectron - (nomo - 1)*mo_set%maxocc
442 : END IF
443 : ! introduce applied potential correction here
444 : ! electron density is adjusted according to applied core correction
445 : ! ref: SS, MT, MWF, JN PRL, 2018, 120, 246801
446 : ! see whether both surface dipole correction and core correction is present in
447 : ! the inputfile
448 192018 : IF (PRESENT(tot_zeff_corr)) THEN
449 : ! find the additional core charges
450 106 : total_zeff_corr = tot_zeff_corr
451 106 : IF (INT(mo_set%maxocc) == 1) total_zeff_corr = total_zeff_corr/2.0_dp
452 106 : delectron = 0.0_dp
453 106 : IF (total_zeff_corr < 0.0_dp) THEN
454 : ! remove electron density from the mos
455 106 : delectron = ABS(total_zeff_corr) - REAL(mo_set%maxocc, KIND=dp)
456 106 : IF (delectron > 0.0_dp) THEN
457 0 : mo_set%occupation_numbers(nomo) = 0.0_dp
458 0 : irmo = CEILING(delectron/REAL(mo_set%maxocc, KIND=dp))
459 0 : DO ir = 1, irmo
460 0 : delectron = delectron - REAL(mo_set%maxocc, KIND=dp)
461 0 : IF (delectron < 0.0_dp) THEN
462 0 : mo_set%occupation_numbers(nomo - ir) = -delectron
463 : ELSE
464 0 : mo_set%occupation_numbers(nomo - ir) = 0.0_dp
465 : END IF
466 : END DO
467 0 : nomo = nomo - irmo
468 0 : IF (mo_set%occupation_numbers(nomo) == 0.0_dp) nomo = nomo - 1
469 106 : ELSEIF (delectron < 0.0_dp) THEN
470 106 : mo_set%occupation_numbers(nomo) = -delectron
471 : ELSE
472 0 : mo_set%occupation_numbers(nomo) = 0.0_dp
473 0 : nomo = nomo - 1
474 : END IF
475 0 : ELSEIF (total_zeff_corr > 0.0_dp) THEN
476 : ! add electron density to the mos
477 0 : delectron = total_zeff_corr - REAL(mo_set%maxocc, KIND=dp)
478 0 : IF (delectron > 0.0_dp) THEN
479 0 : mo_set%occupation_numbers(nomo + 1) = REAL(mo_set%maxocc, KIND=dp)
480 0 : nomo = nomo + 1
481 0 : irmo = CEILING(delectron/REAL(mo_set%maxocc, KIND=dp))
482 0 : DO ir = 1, irmo
483 0 : delectron = delectron - REAL(mo_set%maxocc, KIND=dp)
484 0 : IF (delectron < 0.0_dp) THEN
485 0 : mo_set%occupation_numbers(nomo + ir) = delectron + REAL(mo_set%maxocc, KIND=dp)
486 : ELSE
487 0 : mo_set%occupation_numbers(nomo + ir) = REAL(mo_set%maxocc, KIND=dp)
488 : END IF
489 : END DO
490 0 : nomo = nomo + irmo
491 : ELSE
492 0 : mo_set%occupation_numbers(nomo + 1) = total_zeff_corr
493 0 : nomo = nomo + 1
494 : END IF
495 : END IF
496 : END IF
497 : END IF
498 192804 : nmo = SIZE(mo_set%eigenvalues)
499 :
500 192804 : CPASSERT(nmo >= nomo)
501 192804 : CPASSERT((SIZE(mo_set%occupation_numbers) == nmo))
502 :
503 192804 : mo_set%homo = nomo
504 192804 : mo_set%lfomo = nomo + 1
505 192804 : mo_set%mu = mo_set%eigenvalues(nomo)
506 :
507 : ! Check consistency of the array lengths
508 192804 : IF (PRESENT(eval_deriv)) THEN
509 0 : equal_size = (SIZE(mo_set%occupation_numbers, 1) == SIZE(eval_deriv, 1))
510 0 : CPASSERT(equal_size)
511 : END IF
512 :
513 : ! Quick return, if no smearing information is supplied (TO BE FIXED, smear should become non-optional...)
514 192804 : IF (.NOT. PRESENT(smear)) THEN
515 : ! there is no dependence of the energy on the eigenvalues
516 8 : mo_set%uniform_occupation = .TRUE.
517 8 : IF (PRESENT(eval_deriv)) THEN
518 0 : eval_deriv = 0.0_dp
519 : END IF
520 8 : CALL timestop(handle)
521 8 : RETURN
522 : END IF
523 :
524 : ! Check if proper eigenvalues are already available
525 192796 : IF (smear%method /= smear_list) THEN
526 192772 : IF ((ABS(mo_set%eigenvalues(1)) < 1.0E-12_dp) .AND. &
527 : (ABS(mo_set%eigenvalues(nmo)) < 1.0E-12_dp)) THEN
528 83343 : CALL timestop(handle)
529 83343 : RETURN
530 : END IF
531 : END IF
532 :
533 : ! Perform smearing
534 109453 : IF (smear%do_smear) THEN
535 8700 : IF (PRESENT(xas_env)) THEN
536 18 : i_first = xas_estate + 1
537 18 : nelec = xas_nelectron
538 : ELSE
539 8682 : i_first = 1
540 8682 : IF (smear%fixed_mag_mom == -1.0_dp) THEN
541 0 : nelec = REAL(mo_set%nelectron, dp)
542 : ELSE
543 8682 : nelec = mo_set%n_el_f
544 : END IF
545 : END IF
546 7714 : SELECT CASE (smear%method)
547 : CASE (smear_fermi_dirac)
548 7714 : IF (.NOT. PRESENT(eval_deriv)) THEN
549 : CALL FermiFixed(mo_set%occupation_numbers, mo_set%mu, mo_set%kTS, mo_set%eigenvalues, Nelec, &
550 7714 : smear%electronic_temperature, mo_set%maxocc, xas_estate, occ_estate)
551 : ELSE
552 : ! could be a relatively large matrix, but one could get rid of it by never storing it
553 : ! we only need dE/df * df/de, one could equally parallelize over entries, this could become expensive
554 0 : ALLOCATE (dfde(nmo, nmo))
555 : ! lengthscale could become a parameter, but this is pretty good
556 0 : lengthscale = 10*smear%electronic_temperature
557 :
558 : CALL FermiFixedDeriv(dfde, mo_set%occupation_numbers, mo_set%mu, mo_set%kTS, mo_set%eigenvalues, Nelec, &
559 0 : smear%electronic_temperature, mo_set%maxocc, lengthscale, xas_estate, occ_estate)
560 :
561 : ! deriv of E_{KS}-kT*S wrt to f_i
562 0 : eval_deriv = eval_deriv - mo_set%eigenvalues + mo_set%mu
563 : ! correspondingly the deriv of E_{KS}-kT*S wrt to e_i
564 0 : eval_deriv = MATMUL(TRANSPOSE(dfde), eval_deriv)
565 :
566 0 : DEALLOCATE (dfde)
567 : END IF
568 :
569 : ! Find the lowest fractional occupied MO (LFOMO)
570 36252 : DO imo = i_first, nmo
571 36252 : IF (mo_set%occupation_numbers(imo) < mo_set%maxocc) THEN
572 7714 : mo_set%lfomo = imo
573 7714 : EXIT
574 : END IF
575 : END DO
576 122258 : is_large = ABS(MAXVAL(mo_set%occupation_numbers) - mo_set%maxocc) > smear%eps_fermi_dirac
577 : ! this is not a real problem, but the temperature might be a bit large
578 7714 : CPWARN_IF(is_large, "Fermi-Dirac smearing includes the first MO")
579 :
580 : ! Find the highest (fractional) occupied MO which will be now the HOMO
581 49266 : DO imo = nmo, mo_set%lfomo, -1
582 49266 : IF (mo_set%occupation_numbers(imo) > smear%eps_fermi_dirac) THEN
583 6874 : mo_set%homo = imo
584 6874 : EXIT
585 : END IF
586 : END DO
587 122258 : is_large = ABS(MINVAL(mo_set%occupation_numbers)) > smear%eps_fermi_dirac
588 7714 : IF (is_large) &
589 : CALL cp_warn(__LOCATION__, &
590 : "Fermi-Dirac smearing includes the last MO => "// &
591 680 : "Add more MOs for proper smearing.")
592 :
593 : ! check that the total electron count is accurate
594 7714 : is_large = (ABS(nelec - accurate_sum(mo_set%occupation_numbers(:))) > smear%eps_fermi_dirac*nelec)
595 7714 : CPWARN_IF(is_large, "Total number of electrons is not accurate")
596 :
597 : CASE (smear_energy_window)
598 : ! not implemented
599 962 : CPASSERT(.NOT. PRESENT(eval_deriv))
600 :
601 : ! Define the energy window for the eigenvalues
602 962 : e1 = mo_set%eigenvalues(mo_set%homo) - 0.5_dp*smear%window_size
603 962 : IF (e1 <= mo_set%eigenvalues(1)) THEN
604 0 : CPWARN("Energy window for smearing includes the first MO")
605 : END IF
606 :
607 962 : e2 = mo_set%eigenvalues(mo_set%homo) + 0.5_dp*smear%window_size
608 962 : IF (e2 >= mo_set%eigenvalues(nmo)) &
609 : CALL cp_warn(__LOCATION__, &
610 : "Energy window for smearing includes the last MO => "// &
611 0 : "Add more MOs for proper smearing.")
612 :
613 : ! Find the lowest fractional occupied MO (LFOMO)
614 8264 : DO imo = i_first, nomo
615 8264 : IF (mo_set%eigenvalues(imo) > e1) THEN
616 158 : mo_set%lfomo = imo
617 158 : EXIT
618 : END IF
619 : END DO
620 :
621 : ! Find the highest fractional occupied (non-zero) MO which will be the HOMO
622 7776 : DO imo = nmo, nomo, -1
623 7776 : IF (mo_set%eigenvalues(imo) < e2) THEN
624 158 : mo_set%homo = imo
625 158 : EXIT
626 : END IF
627 : END DO
628 :
629 : ! Get the number of electrons to be smeared
630 962 : edist = 0.0_dp
631 962 : nelec = 0.0_dp
632 :
633 1194 : DO imo = mo_set%lfomo, mo_set%homo
634 232 : nelec = nelec + mo_set%occupation_numbers(imo)
635 1194 : edist = edist + ABS(e2 - mo_set%eigenvalues(imo))
636 : END DO
637 :
638 : ! Smear electrons inside the energy window
639 1194 : DO imo = mo_set%lfomo, mo_set%homo
640 232 : edelta = ABS(e2 - mo_set%eigenvalues(imo))
641 232 : mo_set%occupation_numbers(imo) = MIN(mo_set%maxocc, nelec*edelta/edist)
642 232 : nelec = nelec - mo_set%occupation_numbers(imo)
643 1194 : edist = edist - edelta
644 : END DO
645 :
646 : CASE (smear_list)
647 24 : equal_size = SIZE(mo_set%occupation_numbers, 1) == SIZE(smear%list, 1)
648 24 : CPASSERT(equal_size)
649 168 : mo_set%occupation_numbers = smear%list
650 : ! there is no dependence of the energy on the eigenvalues
651 24 : IF (PRESENT(eval_deriv)) THEN
652 0 : eval_deriv = 0.0_dp
653 : END IF
654 : ! most general case
655 24 : mo_set%lfomo = 1
656 8724 : mo_set%homo = nmo
657 : END SELECT
658 :
659 : ! Check, if the smearing involves more than one MO
660 8700 : IF (mo_set%lfomo == mo_set%homo) THEN
661 584 : mo_set%homo = nomo
662 584 : mo_set%lfomo = nomo + 1
663 : ELSE
664 8116 : mo_set%uniform_occupation = .FALSE.
665 : END IF
666 :
667 : END IF ! do smear
668 :
669 : ! zeros don't count as uniform
670 109453 : mo_set%uniform_occupation = has_uniform_occupation(mo_set=mo_set)
671 :
672 109453 : CALL timestop(handle)
673 :
674 109453 : END SUBROUTINE set_mo_occupation_1
675 :
676 : END MODULE qs_mo_occupation
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