TEXT   62

expectation

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  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.  
  75.    \hat{m}_{j_{1}\ldots j_{n-1};j_{n}}^{\left[n\right]}=\frac{n}{n+1}r_{j_{1}}r_{j_{2}}\ldots r_{j_{n-1}}(\boldsymbol{r}\times\hat{\mathbf{j}})_{j_{n}};\quad\hat{\mathbf{j}}=-ec\boldsymbol{\alpha}
  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.  
  126. This would include excitations from gerade orbitals 1,2,3, and ungerade
  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.  
  245. Advanced/debug flags
  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`.

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