Linear response calculation: *LINEAR

A linear response [163,165] calculation is performed for a given choice of operators, - $\langle\!\langle A; B \rangle\!\rangle_{\omega}$. (Note that minus the linear response properties are written to output.)

In the same RESPONSE CALCULATION THESE LINEAR RESPONSE PROPERTIES CAN BE CALCULATED TOGETHER WITH EXCITATION ENERGIES AND WITH LONG RANGE DISPERSION COEFFICIENTS, BUT NOT TOGETHER WITH QUADRATIC OR CUBIC RESPONSE.

.ABOCHK SETS UP THE ORBITAL PART OF THE #MATH1172# AND #MATH1173# USED IN SOLVING THE LINEAR RESPONSE EQUATION. MAINLY FOR DEBUGGING PURPOSES.

.DIPLEN SETS AND TO DIPOLE OPERATORS.

.DIPLNX/Y/Z SETS AND TO THE X, Y, OR Z COMPONENT OF THE DIPOLE LENGTH OPERATORS, RESPECTIVELY.

.DIPMAG SETS AND TO ANGULAR MOMENTUM OPERATORS.

.DIPMGX/Y/Z SETS AND TO THE X, Y, OR Z COMPONENT OF THE ANGULAR MOMENTUM OPERATORS.

.DIPVEL SETS AND TO THE DIPOLE VELOCITY OPERATORS.

.DIPVLX/Y/Z SETS AND TO THE X, Y, OR Z COMPONENT OF THE DIPOLE VELOCITY OPERATOR, RESPECTIVELY.

.FERMI SETS AND TO BE ALL FERMI-CONTACT OPERATORS FOUND ON THE FILE AOPROPER, I.E. ALL FERMI-CONTACT OPERATORS REQUESTED IN THE **INTEGRALS INPUT MODULE.

.FREQUE
READ *, NFREQ
READ *, FREQ(1:NFREQ)
RESPONSE EQUATIONS ARE EVALUATED AT GIVEN FREQUENCIES. TWO LINES FOLLOWING THIS OPTION MUST CONTAIN 1) THE NUMBER OF FREQUENCIES, 2) FREQUENCIES IN ATOMIC UNITS. REMEMBER TO INCREASE .MAXRM IF MANY FREQUENCIES ARE SPECIFIED.

.ISTOCK SELECTS THE STARTING ROW IN SETTING UP THE ORBITAL PARTS OF #MATH1174# AND #MATH1175# USING THE KEYWORD .ABOCHK. DEFAULT IS 1. MAINLY FOR DEBUGGING PURPOSES.

.MAX IT
READ (LUCMD,*) MAXITL
MAXIMUM NUMBER OF ITERATIONS FOR SOLVING A LINEAR RESPONSE EQUATION. DEFAULT IS 60.

.MAXITO
READ (LUCMD,*) MAXITO
MAXIMUM NUMBER OF ITERATIONS IN THE OPTIMAL ORBITAL ALGORITHM [21]. DEFAULT IS 5.

.MAXOCK SELECTS THE LAST ROW IN SETTING UP THE ORBITAL PARTS OF #MATH1176# AND #MATH1177# USING THE KEYWORD .ABOCHK. DEFAULT IS 6. MAINLY FOR DEBUGGING PURPOSES.

.PRINT
READ *,IPRLR
SETS PRINT LEVEL FOR LINEAR RESPONSE MODULE. DEFAULT IS 2.

.PROPRT
READ '(A)', LABEL
SETS AND TO A GIVEN OPERATOR WITH LABEL; LABEL. (THE CALCULATION OF THE OPERATOR MUST BE SPECIFIED TO THE INTEGRAL MODULE, SEE SECTION .) THIS KEYWORD MAY BE REPEATED FOR DIFFERENT PROPERTIES.

.PV PSO SETS AND IN THE LINEAR RESPONSE FUNCTION TO THE PARITY-VIOLATING OPERATOR AND THE COMPLETE LIST OF PARAMAGNETIC SPIN-ORBIT INTEGRALS. THE .TRPFLG KEYWORD WILL ALSO BE SET BY THIS OPTION.

.PV SO SETS AND IN THE LINEAR RESPONSE FUNCTION TO THE PARITY-VIOLATING OPERATOR AND THE COMPLETE LIST OF PARAMAGNETIC SPIN-ORBIT INTEGRALS. THE .TRPFLG KEYWORD WILL ALSO BE SET BY THIS OPTION.

.PV SO1 SETS AND IN THE LINEAR RESPONSE FUNCTION TO THE PARITY-VIOLATING OPERATOR AND THE ONE-ELECTRON SPIN-ORBIT INTEGRALS. THE .TRPFLG KEYWORD WILL ALSO BE SET BY THIS OPTION.

.PV SO2 SETS AND IN THE LINEAR RESPONSE FUNCTION TO THE PARITY-VIOLATING OPERATOR AND THE TWO-ELECTRON SPIN-ORBIT INTEGRALS. THE .TRPFLG KEYWORD WILL ALSO BE SET BY THIS OPTION.

.QUADMOM SETS AND TO THE QUADRUPOLE OPERATORS.

.QUADXX/XY/XZ/YY/YZ/ZZ SETS AND TO THE XX, XY, XZ, YY, YZ, OR ZZ COMPONENT OF THE QUADRUPOLE OPERATOR, RESPECTIVELY.

.RESTLR RESTART OF RESPONSE CALCULATION. THIS CAN ONLY BE USED IF THE OPERATOR SPECIFIED IS THE SAME WHICH WAS USED LAST IN THE PREVIOUS RESPONSE CALCULATION.

.SOPRSY CALCULATE BOTH AND TO TEST THE QUADRATIC ACCURACY OF THE CALCULATED PROPERTY. MAINLY FOR DEBUGGING PURPOSES.

.FERMI SETS AND TO BE ALL SPIN-DIPOLE OPERATORS FOUND ON THE FILE AOPROPER, I.E. ALL SPIN-DIPOLE OPERATORS REQUESTED IN THE **INTEGRALS INPUT MODULE.

.SPIN-O SETS AND TO SPIN-ORBIT OPERATORS.

.SPNORX/Y/Z SETS AND TO THE X, Y, OR Z COMPONENT OF THE SPIN-ORBIT OPERATOR, RESPECTIVELY.

.THCLR
READ *, THCLR
RELATIVE CONVERGENCE THRESHOLD FOR ALL REQUESTED LINEAR RESPONSE FUNCTIONS. DEFAULT IS 1.0D-3; NOTE THAT THIS NUMBER SHOULD BE AT LEAST 10 TIMES BIGGER THAN THE FINAL GRADIENT NORM IN THE SCF/MCSCF WAVE FUNCTION OPTIMIZATION. THE ACCURACY OF THE LINEAR RESPONSE PROPERTIES WILL BE QUADRATIC IN THIS THRESHOLD; THUS THE DEFAULT CORRESPONDS TO CONVERGENCE TO APPROXIMATELY 6 DIGITS.

.TRIPLET DEFINES AND TO BE TRIPLET OPERATORS. WILL ALSO MAKE A SIMULTANEOUS *LINEAR .SINGLE RESIDUE CALCULATION TO A CALCULATION OF TRIPLET EXCITATION ENERGIES AND TRANSITION MOMENTS.