# Example: PIM: polarizability N2 on silver cluster Ag68¶

Download DIMQM_PIM_Pol.run

Expert option

This example demonstrates how to do calculate static and frequency dependent polarizabilities with the Polarizability Interaction Model (PIM). The example consists of 3 calculations: static polarizability, frequency dependent, and with inclusion of effect of the local field.

When the molecule interacts with a metal nanoparticle, there are two types of interactions: the image field and the local field. The image field is caused by the dipoles induced into the nanoparticle by the molecule’s electron density. This is always taken into account in a DIM/QM calculation. The local field arises by direct interactions of the nanoparticle with an external field. Addition of the LOCALFIELD key causes the DIM/QM calculation to include this effect, but by default this is not included in a DIM/QM calculation.

Static polarizability

$ADFBIN/adf << eor TITLE PIM Static Polarizability, N2 on Ag68 ATOMS N -0.000006 -0.000060 2.302488 N 0.000019 0.000041 3.408628 END BASIS type TZP core none END SYMMETRY NOSYM SCF Converge 1e-6 END INTEGRATION 6 6 6 XC GGA Becke Perdew END AORESPONSE ALDA END DIMQM PIM ALGORITHM BRUTE END DIMPAR Ag rad 1.4445 drude 9.2 0.17 eV bound 5.0 SUBEND XYZ 68 Ag -1.2626801699 -1.1212553334 -7.5641602542 Ag 1.8701101821 -2.1177433283 -0.4836551986 ... SUBEND END eor  Frequency dependent polarizability Difference in the input with respect to static polarizability: $ADFBIN/adf << eor
TITLE PIM Frequency-Dependent Polarizability, N2 on Ag68
AORESPONSE
:: The FREQUENCY is at the Plasmon Max
FREQUENCY 1 3.55 eV
ALDA
END
DIMQM
PIM
ALGORITHM BRUTE
:: Frequency-Dependent
FREQUENCY
END
eor


Frequency dependent polarizability including local field effect

Difference in the input with respect to static polarizability:

\$ADFBIN/adf << eor
TITLE PIM Frequency-Dependent Polarizability with Local Fields, N2 on Ag68
AORESPONSE
:: The FREQUENCY is at the Plasmon Max
FREQUENCY 1 3.55 eV