TEXT   62

# expectation

Guest on 19th May 2022 03:30:19 PM

1.
2.
3.
4. .. index:: *EXCITATION ENERGIES
5. .. _*EXCITATION ENERGIES:
6.
7. =====================
8. \*EXCITATION ENERGIES
9. =====================
10.
11. Calculate excitation energies using time dependent Hartree-Fock or DFT.
12. The excitation energies are found as the lowest generalized eigenvalues
13. of the electronic Hessian. DIRAC supports TDDFT kernels from all ground
14. state functionals included in the code. Currently the iterative
15. eigenvalue solver may fail to converge more than about twenty roots per
16. symmetry.
17.
18. Define excitations and transition moments
19. =========================================
20.
21. .. index:: .EXCITA
22. .. _EXCITATION_ENERGIES_.EXCITA:
23.
24. .EXCITA
25. -------
26.
27. ::
28.
29.     .EXCITA
30.     SYM N
31.
32. Number of excitation energies N calculated in boson symmetry no. SYM.
33. This keyword can be repeated if you want excitation energies in more
34. than one boson symmetry.
35.
36. .. index:: .OPERATOR
37. .. _EXCITATION_ENERGIES_.OPERATOR:
38.
39. .OPERATOR
40. ---------
41.
42. Specification of a transition moment operator (see
43. :ref:one_electron_operators for details). This keyword can be given multiple
44. times to add more operators.
45.
46. .. index:: .EPOLE
47. .. _EXCITATION_ENERGIES_.EPOLE:
48.
49. .EPOLE
50. ------
51.
52. Specification of electric Cartesian multipole operators of order :math:n
53.
54. .. math::
55.
56.     \hat{Q}_{j_{1}\ldots j_{n}}^{\left[n\right]}=-er_{1}r_{2}\ldots r_{j_{n}}
57.
58. for the calculation of transition moments (note that they contribute to one order less in the wave vector). Specify order.
59.
60. *Example:* Electric dipole operators::
61.
62.       .EPOLE
63.       1
64.
65. .. index:: .MPOLE
66. .. _EXCITATION_ENERGIES_.MPOLE:
67.
68. .MPOLE
69. ------
70.
71. Specification of magnetic Cartesian multipole operators of order :math:n
72.
73. .. math::
74.
76.
77.
78. for the calculation of transition moments (note that they contribute to the same order in the wave vector). Specify order.
79.
80. *Example:* Magnetic dipole operators::
81.
82.       .MPOLE
83.       1
84.
85. .. index:: .ANALYZE
86. .. _EXCITATION_ENERGIES_.ANALYZE:
87.
88. .ANALYZE
89. --------
90.
91. Analyze solution vectors and show the most important excitations at the
92. orbital level.
93.
94. .. index:: .INTENS
95. .. _EXCITATION_ENERGIES_.INTENS:
96.
97. .INTENS
98. -------
99.
100. Invoke calculation of oscillator strengths. Followed by oscillator strengths to order k in the wave vector, which must be zero.
101.
102. *Example:* ::
103.
104.      .INTENS
105.      0
106.
107. Control variational parameters
108. ==============================
109.
110. .. index:: .OCCUP
111. .. _EXCITATION_ENERGIES_.OCCUP:
112.
113. .OCCUP
114. ------
115.
116. For each fermion ircop give an :ref:orbital_strings of inactive orbitals from
117. which excitations are allowed. By default excitations from all occupied
118. orbitals are included in the generalized eigenvalue problem.
119.
120. Example: ::
121.
122.     .OCCUP
123.     1..3
124.     7,8
125.
127. orbitals 7 and 8.
128.
129. .. index:: .VIRTUA
130. .. _EXCITATION_ENERGIES_.VIRTUA:
131.
132. .VIRTUA
133. -------
134.
135. For each fermion ircop give an :ref:orbital_strings
136. of virtual orbitals
137. to which excitations are allowed. By default excitations to all virtal
138. orbitals are included in the generalized eigenvalue problem.
139.
140. .. index:: .SKIPEE
141. .. _EXCITATION_ENERGIES_.SKIPEE:
142.
143. .SKIPEE
144. -------
145.
146. Exclude all rotations between occupied positive-energy and virtual
147. positive-energy orbitals.
148.
149. .. index:: .SKIPEP
150. .. _EXCITATION_ENERGIES_.SKIPEP:
151.
152. .SKIPEP
153. -------
154.
155. Exclude all rotations between occupied positive-energy and virtual
156. negative-energy orbitals.
157.
158. Control reduced equations
159. =========================
160.
161. .. index:: .MAXITR
162. .. _EXCITATION_ENERGIES_.MAXITR:
163.
164. .MAXITR
165. -------
166.
167. Maximum number of iterations.
168.
169. *Default:* ::
170.
171.     .MAXITR
172.      30
173.
174. .. index:: .MAXRED
175. .. _EXCITATION_ENERGIES_.MAXRED:
176.
177. .MAXRED
178. -------
179.
180. Maximum dimension of matrix in reduced system.
181.
182. *Default:* ::
183.
184.     .MAXRED
185.      200
186.
187. .. index:: .THRESH
188. .. _EXCITATION_ENERGIES_.THRESH:
189.
190. .THRESH
191. -------
192.
193. Threshold for convergence of reduced system.
194.
195. *Default:* ::
196.
197.     .THRESH
198.      1.0D-5
199.
200. Control integral contributions
201. ==============================
202.
203. The user is encouraged to experiment with these options since they may
204. have an important effect on run time.
205.
206. .. index:: .INTFLG
207. .. _EXCITATION_ENERGIES_.INTFLG:
208.
209. .INTFLG
210. -------
211.
212. Specify what two-electron integrals to include
213. (default: :ref:HAMILTONIAN_.INTFLG under :ref:**HAMILTONIAN).
214.
215. .. index:: .CNVINT
216. .. _EXCITATION_ENERGIES_.CNVINT:
217.
218. .CNVINT
219. -------
220.
221. Set threshold for convergence before adding SL and SS integrals to
222. SCF-iterations.
223.
224. *2 (real) Arguments:* ::
225.
226.     .CNVINT
227.      CNVXQR(1) CNVXQR(2)
228.
229. *Default:* Very large numbers.
230.
231. .. index:: .ITRINT
232. .. _EXCITATION_ENERGIES_.ITRINT:
233.
234. .ITRINT
235. -------
236.
237. Set the number of iterations before adding SL and SS integrals to
238. SCF-iterations.
239.
240. *Default:* ::
241.
242.     .ITRINT
243.      1 1
244.
246. ====================
247.
248. .. index:: .E2CHEK
249. .. _EXCITATION_ENERGIES_.E2CHEK:
250.
251. .E2CHEK
252. -------
253.
254. Generate a complete set of trial vector which implicitly allows the
255. explicit construction of the electronic Hessian. Only to be used for
256. small systems !
257.
258. .. index:: .ONLYSF
259. .. _EXCITATION_ENERGIES_.ONLYSF:
260.
261. .ONLYSF
262. -------
263.
264. Only call FMOLI in sigmavector routine: only generate one-index
265. transformed Fock matrix  :cite:Saue2003.
266.
267. .. index:: .ONLYSG
268. .. _EXCITATION_ENERGIES_.ONLYSG:
269.
270. .ONLYSG
271. -------
272.
273. Only call FMOLI in sigmavector routine: 2-electron Fock matrices using
274. one-index transformed densities :cite:Saue2003.