Quadrimer vs two dimers

05 December, 2023

Source: vignettes/15_quadrimer/15_quadrimer.Rmd

Objective

This example illustrates the import of a TERMS-exported collective T-matrix as an input (effective) scatterer. We compare the simulation of a quadrimer of spheres to that of two dimers (with the same geometry).

ModeAndScheme 1 3 
MultipoleCutoff 15
Wavelength 400
Medium 1.7689 # epsilon of water
Incidence 0 1.570796 0 2 # k_x, E_y
TmatrixFiles 1
"collective_dimer_400.tmat" 

MapQuantity   2 E # map I=|E|^2
SpacePoints   0   0   1   -75   75   300   -75   75   300   
OutputFormat HDF5 map_twodimers

# 2 dimers displaced along y
# aspect ratio irrelevant here, picking 100 to check effect on raster map
Scatterers 2
TF1 0.0 -30.0  0.0 30 0 0.0 0.0  100
TF1 0.0  30.0  0.0 30 0 0.0 0.0  100

Near-field

As expected, the local fields cannot be calculated within the circumbscribed sphere of a dimer described as an input T-matrix.

Far-field

remarkably, the far-field cross-sections are quite accurate even though the Rayleigh hypothesis is badly violated.

Last run: 05 December, 2023