dimer_linear

library(cda)
library(rgl)
library(ggplot2)

# dielectric function
wvl <- seq(400, 900)
gold <- epsAu(wvl)

Influence of the particle separation

  
dimer <- function(d=100, ...){
  
  r <- cbind(c(0,0), c(-d/2, d/2), c(0, 0))
  sizes <- equal_sizes(a=50, b=20, c=20, N=2)  
  angles <- matrix(0, ncol=3, nrow=2)

  cl <- list(r=r, sizes=sizes, angles=angles)
  linear_extinction_spectrum(cl, material = gold)
  
}
params <- data.frame(d=seq(100, 500, length=50))
comparison <- mdply(params, dimer)

p <- 
  ggplot(data=comparison) + 
  facet_grid(variable~., scales="free") +
  geom_line(aes(wavelength, value, 
                colour=d, group=d)) +
  labs(y=expression(sigma[ext]*" /"*nm^2),
       x=expression(wavelength*" /"*nm), colour="distance /nm") 

p