:orphan: .. index:: *LINEAR RESPONSE .. _*LINEAR RESPONSE: ================= \*LINEAR RESPONSE ================= Linear Response module written by T. Saue and H. J. Aa. Jensen :cite:Saue2003. General control statements ========================== .. index:: .PRINT .. _LINEAR_RESPONSE_.PRINT: .PRINT ------ Print level. *Default:* :: .PRINT 0 Definition of the linear response function ========================================== .. index:: .A OPERATOR .. _LINEAR_RESPONSE_.A OPERATOR: .A OPERATOR ----------- Specification of the A operator (see :ref:one_electron_operators for details). .. index:: .B OPERATOR .. _LINEAR_RESPONSE_.B OPERATOR: .B OPERATOR ----------- Specification of the B operator (see :ref:one_electron_operators for details). .. index:: .OPERATORS .. _LINEAR_RESPONSE_.OPERATORS: .OPERATORS ---------- Specification of both the A and B operators (see :ref:one_electron_operators for details). .. index:: .EPOLE .. _LINEAR_RESPONSE_.EPOLE: .EPOLE ------ Specification of electric Cartesian multipole operators of order L . Specify order. *Example:* Electric dipole operators :: .EPOLE 1 .. index:: .MPOLE .. _LINEAR_RESPONSE_.MPOLE: .MPOLE ------ Specification of magnetic Cartesian multipole operators of order L . Specify order. *Example:* Magnetic dipole operators :: .MPOLE 1 .. index:: .TRIAB .. _LINEAR_RESPONSE_.TRIAB: .TRIAB ------ Enforce triangularity of response function. .. math:: \langle\langle A; B \rangle\rangle_\omega = \langle\langle B; A \rangle\rangle_\omega Only one function is calculated. *Default:* Deactivated. .. index:: .B FREQ .. _LINEAR_RESPONSE_.B FREQ: .B FREQ ------- Specify frequencies of operator B. *Example:* 3 different frequencies. :: .B FREQ 3 0.001 0.002 0.01 *Default:* Static case. :: .B FREQ 1 0.0 .. index:: .IMAGIN .. _LINEAR_RESPONSE_.IMAGIN: .IMAGIN ------- Employ imaginary frequencies. .. index:: .ALLCMB .. _LINEAR_RESPONSE_.ALLCMB: .ALLCMB ------- Form all possible combinations even if imaginary. *Default:* Deactivated. .. index:: .UNCOUP .. _LINEAR_RESPONSE_.UNCOUP: .UNCOUP ------- Uncoupled calculation. Control variational parameters ============================== .. index:: .OCCUP .. _LINEAR_RESPONSE_.OCCUP: .OCCUP ------ For each fermion ircop give an :ref:orbital_strings of inactive orbitals to include in the linear response calculation. .. index:: .VIRTUA .. _LINEAR_RESPONSE_.VIRTUA: .VIRTUA ------- For each fermion ircop give an :ref:orbital_strings of virtual orbitals to include in the linear response calculation. .. index:: .SKIPEE .. _LINEAR_RESPONSE_.SKIPEE: .SKIPEE ------- Exclude all rotations between occupied positive-energy and virtual positive-energy orbitals. .. index:: .SKIPEP .. _LINEAR_RESPONSE_.SKIPEP: .SKIPEP ------- Exclude all rotations between occupied positive-energy and virtual negative-energy orbitals. Control reduced equations ========================= .. index:: .MAXITR .. _LINEAR_RESPONSE_.MAXITR: .MAXITR ------- Maximum number of iterations. *Default:* :: .MAXITR 30 .. index:: .MAXRED .. _LINEAR_RESPONSE_.MAXRED: .MAXRED ------- Maximum dimension of matrix in reduced system. *Default:* :: .MAXRED 200 .. index:: .THRESH .. _LINEAR_RESPONSE_.THRESH: .THRESH ------- Threshold for convergence of reduced system. *Default:* :: .THRESH 1.0D-5 Control integral contributions ============================== The user is encouraged to experiment with these options since they may have an important effect on run time. .. index:: .INTFLG .. _LINEAR_RESPONSE_.INTFLG: .INTFLG ------- Specify what two-electron integrals to include (default: :ref:HAMILTONIAN_.INTFLG under :ref:**HAMILTONIAN). .. index:: .CNVINT .. _LINEAR_RESPONSE_.CNVINT: .CNVINT ------- Set threshold for convergence before adding SL and SS integrals to SCF-iterations. *2 (real) Arguments:* :: .CNVINT CNVXQR(1) CNVXQR(2) *Default:* Very large numbers. .. index:: .ITRINT .. _LINEAR_RESPONSE_.ITRINT: .ITRINT ------- Set the number of iterations before adding SL and SS integrals to SCF-iterations. *Default:* :: .ITRINT 1 1 Control trial vectors ===================== .. index:: .REAXVC .. _LINEAR_RESPONSE_.REAXVC: .REAXVC ------- Read solution vectors from file XVCFIL :: .REAXVC XVCFIL *Default:* No restart on solution vectors. The file has to have six characters. Make sure there is no blank character in front of the file name. For a restart on solution vectors it is useful to set :: .REAXVC XVCFIL .ITRINT 0 0 otherwise LS-integrals (and SS-integrals) are switched on later and one may first iterate away and then back to a possibly converged response vector. Often you have a converged SCF wave function along with a response vector. In this case make sure that :: **DIRAC #.WAVE FUNCTION is commented out. Make then also sure that you use the DFCOEF file which has been obtained in the *same* calculation as the response vector file. Otherwise you may observe more response solver iterations than necessary. .. index:: .XLRNRM .. _LINEAR_RESPONSE_.XLRNRM: .XLRNRM ------- Normalize trial vectors. Using normalized trial vectors will reduce efficiency of screening. CLARIFY! *Default:* Use un-normalized vectors. Advanced/debug flags ==================== .. index:: .E2CHEK .. _LINEAR_RESPONSE_.E2CHEK: .E2CHEK ------- Generate a complete set of trial vector which implicitly allows the explicit construction of the electronic Hessian. Only to be used for small systems ! .. index:: .ONLYSF .. _LINEAR_RESPONSE_.ONLYSF: .ONLYSF ------- Only call FMOLI in sigmavector routine: only generate one-index transformed Fock matrix :cite:Saue2003. .. index:: .ONLYSG .. _LINEAR_RESPONSE_.ONLYSG: .ONLYSG ------- Only call FMOLI in sigmavector routine: 2-electron Fock matrices using one-index transformed densities :cite:Saue2003. .. index:: .STERNHEIM .. _LINEAR_RESPONSE_.STERNHEIM: .STERNHEIM ---------- Set diagonal elements of orbital part of Hessian equal to .. math:: -2 m c^2 for rotations between occupied positive-energy and virtual negative-energy orbitals. *Default:* Deactivated. .. index:: .STERNC .. _LINEAR_RESPONSE_.STERNC: .STERNC ------- (Sternheim complement) allows to separate basis set incompleteness from the replacement of an inner sum over negative-energy orbitals only by the full sum. In order to benefit from this functionality (only for specialists !), you should run with print level 2 under properties. Then you can do a sequence of calculations: 1) .SKIPEP 2) .STERNH 3) .STERNC The diamagnetic contribution of 1) is the non-relativistic expectation value, whereas 2) is the Sternheim approximation, that is replacing orbital energy differences with .. math:: -2 m c^2 With no basis set incompleteness the sum of the diamagnetic contribution 2) and the paramagnetic contribution 3) should equal the diamagnetic contribution of 1). *Default:* Deactivated. .. index:: .COMPRESSION .. _LINEAR_RESPONSE_.COMPRESSION: .COMPRESSION ------------ Reduce number of orbital variation parameters by checking corresponding elements of gradient vector against a threshold. This may reduce memory. *Default:* No compression. :: .COMPRESSION 0.0 .. index:: .NOPREC .. _LINEAR_RESPONSE_.NOPREC: .NOPREC ------- No preconditioning of initial trial vectors. *Default:* Preconditioning of trial vectors. .. index:: .RESFAC .. _LINEAR_RESPONSE_.RESFAC: .RESFAC ------- New trial vector will be generated only for variational parameter classes whose residual has a norm that is larger than a fraction 1/RESFAC of the maximum norm. *Default:* :: .RESFAC 1000.0