Magnetizabilities

The calculation of molecular magnetizabilities is invoked by the keyword .MAGNET in the **PROPERTIES input module. Thus a complete input file for the calculation of molecular magnetizabilities will look like:

**DALTON INPUT
.RUN PROPERTIES
**WAVE FUNCTIONS
.HF
**PROPERTIES
.MAGNET
**END OF DALTON INPUT

This will invoke the calculation of molecular magnetizabilities using London Atomic Orbitals to ensure fast basis set convergence and gauge-origin independent results. The natural connection [64] is used in order to get numerically accurate results. By default the center of mass is chosen as gauge origin.

For a SOPPA or SOPPA(CCSD) calculation of molecular magnetizabilities, the additional keywords .SOPPA or .SOPPA(CCSD) have to be specified in the **PROPERTIES input module. For SOPPA an MP2 calculation has to be requested by the keyword .MP2 in the **WAVE FUNCTIONS input module, whereas for SOPPA(CCSD) a CCSD calculation has to be requested by the keyword .CC in the **WAVE FUNCTIONS input module with the *CC INPUT option .SOPPA(CCSD). This will also automatically disable the use of London orbitals.

For a CTOCD-DZ calculation of molecular magnetizabilities, the additional keyword .CTOCD has to be specified in the **PROPERTIES input module. This will automatically disable the use of London orbitals. .SOPPA / .SOPPA(CCSD) and .CTOCD could be used together to get SOPPA / SOPPA(CCSD) molecular magnetizabilities using the CTOCD-DZ formalism. Information about suitable basis sets for CTOCD-DZ calculations can be found in the section 10.9.1.

The augmented cc-pVXZ basis sets of Dunning and coworkers [65,66,67,68] have been shown to give to give excellent results for magnetizabilities [56,69,70], and these basis sets are obtainable from the basis set library.

Notice that a general print level of 2 or higher is needed in order to get the individual contributions (relaxation, one- and two-electron expectation values and so on) to the total magnetizability.

If more close control of the different parts of the calculation of the magnetizability is wanted, we refer the reader to the section describing the options available. The modules that controls the calculation of molecular magnetizabilities are:

*EXPECT

Controls the calculation of one-electron expectation values contributing to the diamagnetic magnetizability.

*GETSGY

Controls the set up of the right-hand sides (gradient terms) as well as the calculation of two-electron expectation values and reorthonormalization terms.

*LINRES

Controls the solution of the magnetic response equations

*RELAX

Controls the multiplication of solution and right-hand side vectors into relaxation contributions