General: **RESPONSE

General-purpose directives are given in the **RESPONSE   section.

.NOAVDI   Do not use Fock type decoupling of the two-electron density matrix. Add instead of to approximate orbital diagonal.

.INPTES   Input test. For debugging purposes only. The program stops after the input section.

.HIRPA   Invoke the higher RPA approximation for the calculation of linear response properties. This approximation is identical to that of McKoy and coworkers [85, 86]. The requirements to the preceding wave function calculation is the same as for the .SOPPA   keyword.

.MAXPHP  
READ *, MAXPHP
Change the maximum dimension of subspace. Default is 100. PHP is a subblock of the CI matrix which is calculated explicitly in order to obtain improved CI trial vectors compared to the straight Davidson algorithm[87]. The configurations corresponding to the lowest diagonal elements are selected, unless .PHPRESIDUAL is specified. MAXPHP is the maximum dimension of PHP, the actual dimension will be less if MAXPHP will split degenerate configurations.

.MAXRM  
READ *, MAXRM
Change the maximum dimension of the reduced space. Default is 200. When solving a linear system of equations or an eigenvalue equation, the reduced space is increased by 1 in each iteration. For single root calculations this should exceed the number of iterations required.

.NODOIT   Turns off direct one-index transformation [88]. In this way all one-index transformed integrals are stored on disk.

.NOITRA   No integral transformation. Normally the two-electron integrals are transformed in the beginning of a response calculation. In some cases this is not desirable, e.g., if the response part is only used for calculating average values of operator, or if the transformed two-electron integrals already exist from a previous response calculation.

.S0MIX   Sum rule is calculated in mixed representation, that is, calculate provided that dipole length and velocity integrals are available on the property integral file (calculated with **HERMIT   options .DIPLEN   and .DIPVEL  ). The calculated quantity gives a measure of the quality of the basis set .

.OPTORB   Orbital trial vectors are calculated with optimal orbital trial  vector algorithm [7].

.ORBSFT  
READ *, ORBSFT
Change the amount for shifting the orbital diagonal  of the MCSCF Hessian. May be used if there is a large number of negative eigenvalues. Default is .

.ORBSPC   Calculation with only orbital operators.

.PHPRES   Select configurations for PHP matrix based on largest residual rather than lowest diagonal elements.

.PROPAV  
READ '(A)', LABEL
Property average . The average value of an operator is calculated. The line following this option must contain the label of the operator given in the integral property file. (See section .)

.QRREST   Restart quadratic response  calculation.

.RSPCI   Configuration interaction   response calculation.

.SOPPA   Required, no defaults.
The SOPPA   flag requires that the preceding SIRIUS calculation has generated the MP2 correlation coefficients and written them to disk. (Set .RUN RESPONSE   in **DALTON   input as well as .HF   and .MP2   in **WAVE FUNCTION  ). See example input in Chapter .

.SOPW4   Calculate explicitly the W4 term described by Odderhede et al. [89]. This term is already included in the normal SOPPA   result, and used mostly for comparing to older calculations. Note that this keyword requires that .SOPPA   is set.

.TRPFLG   Triplet flag. This option is set whenever triplet (spin-dependent)  operators must be used in a response calculation [90, 91]