nanop (version 2.0-1)

GrSAS: Functions to calculate the gamma baseline term for PDF

Description

Functions to calculate analytically the gamma baseline term given a particle lattice and size parameters.

Usage

GrSAS(r, Rcore=NA, Rpart, latticep, latticepShell=NA, 
    N1, N2=NA, sym, symShell=NA)   
GrSASCS(r, Rcore=NA, Rpart, latticep, latticepShell=NA, 
    N1, N2=NA, sym, symShell=NA)

Value

numeric vector of function values.

Rdversion

1.1

Details

Function GrSAS can be used for both uniform and core/shell particles. In the second case the uniform model is applied with scattering length density averaged through the nanoparticle. Function GrSASCS calculates baseline term for core/shell particles using model described in Glatter, 1979.

References

Glatter O. (1979): The interpretation of real-space information from small-angle scattering experiments. J. Appl. Cryst., 12, 166--175.

See Also

calcPDF, calcQDepPDF

Examples

## calculate baseline term for uniform particle			
gammaR <- GrSAS(r=seq(0.01, 30, 0.01), Rpart=15, 
    latticep=c(4.3, 7.02), sym="hcp", N1=4)
plot(seq(0.01, 30, 0.01), gammaR, type="l")

## compare with baseline computed as Fourier transform 
## of the total scattering function:
Zn <- createAtom("Zn")
S <- createAtom("S")
part <- simPart(atoms=list(Zn,S), r=15, latticep=c(4.3, 7.02), 
    sym="hcp")
gQSAS <- calcTotalScatt(part, type="neutron",  minQ=0.001, 
    maxQ=0.9, dQ=0.005)
gammaR2 <- calcQDepPDF(part, minR=0.01, maxR=30, dr=0.01, 
    maxQ=.85, minQ=0.001, verbose=20,
    preTotalScat=list(Q=gQSAS$Q, gQ=gQSAS$gQ))
lines(gammaR2$r, gammaR2$gr, col=2)