http://micro.stanford.edu/mediawiki/index.php?action=history&feed=atom&title=Fit_a0EB.m 2026-07-05T17:58:04Z Revision history for this page on the wiki MediaWiki 1.39.7 http://micro.stanford.edu/mediawiki/index.php?title=Fit_a0EB.m&diff=3140&oldid=prev 2009-02-06T07:16:52Z

<p>New page: function [a0, Ecoh, B] = fit_a0EB( datafile ) %data = load(&#039;Elatt.B.dat&#039;); data = load( datafile ); a = data(:,1); E = data(:,3); V = a.^3; n = 11; % number of atoms in computational cel...</p> <p><b>New page</b></p><div>function [a0, Ecoh, B] = fit_a0EB( datafile )<br /> <br /> %data = load(&#039;Elatt.B.dat&#039;);<br /> data = load( datafile );<br /> <br /> a = data(:,1);<br /> E = data(:,3);<br /> V = a.^3;<br /> n = 11; % number of atoms in computational cell<br /> N = 11; % number of atoms in an FCC unit cell<br /> <br /> [P1, S1] = polyfit(a, E, 2);<br /> [P2, S2] = polyfit(V, E/n*N, 2);<br /> <br /> a0 = -P1(2)/(2*P1(1));<br /> V0 = a0^3;<br /> Ecoh = polyval(P1,a0)/n;<br /> B = 2*V0*P2(1) * 160.2; % conversion from eV/A^3 to GPa<br /> <br /> disp(sprintf(&#039;a0 = %.6f (A)&#039;,a0));<br /> disp(sprintf(&#039;Ecoh = %.6f (eV)&#039;,Ecoh));<br /> disp(sprintf(&#039;B = %.6f (GPa)&#039;,B));<br /> <br /> aaxis = [0:0.01:1]*(max(a)-min(a))+min(a);<br /> Efit = polyval(P1,aaxis);<br /> vaxis = aaxis.^3;<br /> <br /> figure(1)<br /> plot(a,E,&#039;o&#039;,aaxis,Efit,&#039;-&#039;);</div>

Euniv