Figure 5.19:

Langmuir isotherm for CO uptake on Ru.

Code for Figure 5.19

Text of the GNU GPL.

main.m


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% Copyright (C) 2001, James B. Rawlings and John G. Ekerdt
%
% This program is free software; you can redistribute it and/or
% modify it under the terms of the GNU General Public License as
% published by the Free Software Foundation; either version 2, or (at
% your option) any later version.
%
% This program is distributed in the hope that it will be useful, but
% WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
% General Public License for more details.
%
% You should have received a copy of the GNU General Public License
% along with this program; see the file COPYING.  If not, write to
% the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
% MA 02111-1307, USA.

% assoc_isotherm.m ;   fit to nonlinear form of isotherm
% jbr, 2/23/98
%

% This m-file loads data file 'assoc_isotherm.rdat'.
global CO P CO_s
%Pdata = [100,1.28;150,1.63;200,1.77;250,1.94;300,2.06;400,2.21];

Pdata = load ('assoc_isotherm.rdat');

ndata = size(Pdata,1);
ngrid = 20;
P = Pdata(:,1);
b = 1e6/(760*82.06*373);
CO =b*P;
CO_s = Pdata(:,2);
data = [CO CO_s];
%save -ascii assoc_isotherm.xdat data;

%
% Find the best K_CO and c_m values for the isotherm
%

optimset ('TolFun', 1e-12);
guess = [10; 1];
[x, obj, info] = fminunc (@f, guess);
info;
K_CO = x(1);
c_m = x(2);

CO_grid = linspace(CO(1), CO(ndata), ngrid)';

CO_s_opt =  (K_CO*c_m*CO_grid)./(1 + K_CO*CO_grid);

output = [CO_grid CO_s_opt];
%save -ascii assoc_isotherm.fit output;
save assoc_isotherm.dat output data

if (~ strcmp (getenv ('OMIT_PLOTS'), 'true')) % PLOTTING
plot (output(:,1),output(:,2),data(:,1),data(:,2),'o');
axis ([3.8,18,1,2.4]);
% TITLE
end % PLOTTING

assoc_isotherm.rdat


f.m


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function sqerror = f(x)
  global CO CO_s
  K_CO = x(1);
  c_m = x(2);
  CO_sc =  (c_m*K_CO*CO)./(1 + K_CO*CO);
  diff = CO_s - CO_sc;
  sqerror = diff'*diff;