%% Information
%dGCALC(GA,GB,xB,T,I0AB,I1AB,I2AB,I3AB,I4AB,I5AB) is for calculating delta Gibbs of binary single solution system..
% I0AB,I1AB,I2AB,I3AB,I4AB,I5AB are parameters of Redlich-Kister binary excess model (Redlich & Kister, 1948)
%Contact: x.chen@mpie.de
function[dG]= dGCALC(varargin)
narginchk(5,10)
R=8.314;
if nargin==5
GA=varargin{1};
GB=varargin{2};
xB=varargin{3};
xA=1-xB;
T=varargin{4};
IAB=varargin{5};
switch xB
case {0,1}
dG=-GA+GB+R*T*(log(xB+0.00001)-log(xA+0.00001))+(1-2*xB)*IAB; %+0.00001 for preventing Inf cases
otherwise
dG=-GA+GB+R*T*(log(xB)-log(xA))+(1-2*xB)*IAB;
end
end
if nargin==6
GA=varargin{1};
GB=varargin{2};
xB=varargin{3};
xA=1-xB;
T=varargin{4};
IAB=varargin{5}+varargin{6}*(1-2*xB);%???????
dIAB=varargin{6}*(-2);
switch xB
case {0,1}
dG=-GA+GB+R*T*(log(xB+0.00001)-log(xA+0.00001))+(1-2*xB)*IAB;% +xA*xB*dIAB=0 omit
otherwise
dG=-GA+GB+R*T*(log(xB)-log(xA))+(1-2*xB)*IAB+xA*xB*dIAB;
end
end
if nargin==7
GA=varargin{1};
GB=varargin{2};
xB=varargin{3};
xA=1-xB;
T=varargin{4};
IAB=varargin{5}+varargin{6}*(1-2*xB)+varargin{7}*(1-2*xB)^2;
dIAB=varargin{6}*(-2)+varargin{7}*(8*xB-4);%???????
switch xB
case {0,1}
dG=-GA+GB+R*T*(log(xB+0.00001)-log(xA+0.00001))+(1-2*xB)*IAB;
otherwise
dG=-GA+GB+R*T*(log(xB)-log(xA))+(1-2*xB)*IAB+xA*xB*dIAB;
end
end
if nargin==8
GA=varargin{1};
GB=varargin{2};
xB=varargin{3};
xA=1-xB;
T=varargin{4};
IAB=varargin{5}+varargin{6}*(1-2*xB)+varargin{7}*(1-2*xB)^2+varargin{8}*(1-2*xB)^3;
dIAB=varargin{6}*(-2)+varargin{7}*(8*xB-4)+varargin{8}*(-6*(2*xB-1)^2);
switch xB
case {0,1}
dG=-GA+GB+R*T*(log(xB+0.00001)-log(xA+0.00001))+(1-2*xB)*IAB;
otherwise
dG=-GA+GB+R*T*(log(xB)-log(xA))+(1-2*xB)*IAB+xA*xB*dIAB;
end
end
if nargin==9
GA=varargin{1};
GB=varargin{2};
xB=varargin{3};
xA=1-xB;
T=varargin{4};
IAB=varargin{5}+varargin{6}*(1-2*xB)+varargin{7}*(1-2*xB)^2+varargin{8}*(1-2*xB)^3+varargin{9}*(1-2*xB)^4;
dIAB=varargin{6}*(-2)+varargin{7}*(8*xB-4)+varargin{8}*(-6*(2*xB-1)^2)+varargin{9}*(8*(2*xB-1)^3);
switch xB
case {0,1}
dG=-GA+GB+R*T*(log(xB+0.00001)-log(xA+0.00001))+(1-2*xB)*IAB;
otherwise
dG=-GA+GB+R*T*(log(xB)-log(xA))+(1-2*xB)*IAB+xA*xB*dIAB;
end
end
if nargin==10
GA=varargin{1};
GB=varargin{2};
xB=varargin{3};
xA=1-xB;
T=varargin{4};
IAB=varargin{5}+varargin{6}*(1-2*xB)+varargin{7}*(1-2*xB)^2+varargin{8}*(1-2*xB)^3+varargin{9}*(1-2*xB)^4+varargin{10}*(1-2*xB)^5;
dIAB=varargin{6}*(-2)+varargin{7}*(8*xB-4)+varargin{8}*(-6*(2*xB-1)^2)+varargin{9}*(8*(2*xB-1)^3)+varargin{10}*(-10*(2*xB - 1)^4);
switch xB
case {0,1}
dG=-GA+GB+R*T*(log(xB+0.00001)-log(xA+0.00001))+(1-2*xB)*IAB;
otherwise
dG=-GA+GB+R*T*(log(xB)-log(xA))+(1-2*xB)*IAB+xA*xB*dIAB;
end
end
end