function result = mie2(eps1, mu1, x) % Computation of Mie Efficiencies for given complex % permittivity and permeability ratios eps1=eps1'+ieps1", % mu1=mu1'+imu1" between inside and outside of the sphere % and size parameter x=k0*a, where k0= wave number in ambient % medium, a=sphere radius, using complex Mie Coefficients % an and bn for n=1 to nmax,. % Bohren and Huffman (1983) BEWI:TDD122, p. 103,119-122,477. % Result: Efficiencies for extinction (qext), % scattering (qsca), absorption (qabs), backscattering (qb), % asymmetry parameter (asy=) and (qratio=qb/qsca). % C. Mätzler, July 2002. if x==0 % To avoid a singularity at x=0 result=[0 0 0 0 0 1.5]; elseif x>0 % This is the normal situation nmax=round(2+x+4*x.^(1/3)); n1=nmax-1; n=(1:nmax);cn=2*n+1; c1n=n.*(n+2)./(n+1); c2n=cn./n./(n+1); x2=x.*x; f=mie2_ab(eps1,mu1,x); anp=(real(f(1,:))); anpp=(imag(f(1,:))); bnp=(real(f(2,:))); bnpp=(imag(f(2,:))); g1(1:4,nmax)=[0; 0; 0; 0]; % displaced numbers used for g1(1,1:n1)=anp(2:nmax); % asymmetry parameter, p. 120 g1(2,1:n1)=anpp(2:nmax); g1(3,1:n1)=bnp(2:nmax); g1(4,1:n1)=bnpp(2:nmax); dn=cn.*(anp+bnp); q=sum(dn); qext=2*q/x2; en=cn.*(anp.*anp+anpp.*anpp+bnp.*bnp+bnpp.*bnpp); q=sum(en); qsca=2*q/x2; qabs=qext-qsca; fn=(f(1,:)-f(2,:)).*cn; gn=(-1).^n; f(3,:)=fn.*gn; q=sum(f(3,:)); qb=q*q'/x2; asy1=c1n.*(anp.*g1(1,:)+anpp.*g1(2,:)+bnp.*g1(3,:)+bnpp.*g1(4,:)); asy2=c2n.*(anp.*bnp+anpp.*bnpp); asy=4/x2*sum(asy1+asy2)/qsca; qratio=qb/qsca; result=[qext qsca qabs qb asy qratio]; end;