gamma function
link for downloading gamma function code
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<h1 style="margin: 0.0px 0.0px 16.0px 0.0px; font: 24.0px Times; color: #001cc1"><b>FORTRAN code for the Gamma function</b></h1>
<p class="p2"><span class="s1"><a href="http://people.chem.byu.edu/rbshirts/research/gamma-function/lngam.for"><span class="Apple-converted-space"> </span>click here to download the FORTRAN code</a></span></p>
<p class="p3">89 lines, 2878 bytes</p>
<h3 style="margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times; color: #001cc1"><b>The excitation probability distribution for microcanonical energies</b></h3>
<p class="p3">The one-particle excitation probability distribution for states in a microcanonical ensemble (fixed number of particles, fixed energy, and fixed volume) is not given by the exponential Boltzmann distribution except in the limit of an infinite number of particles. The correct distribution, at least in many cases, is accurately approximated by a ratio of two Gamma functions. The FORTRAN code indicated here will evaluate the natural logarithm of the Gamma function and its first two derivatives. The accuracy is approximately 14 decimal places. The method used is Pade' approximants to the asymptotic series for large arguments and recursion downward.</p>
<p class="p3">These results are discussed in <i>J. Chem. Phys.</i> <b>117</b>, 5564-5575 (2002) with further application for the case of hard spheres in <i>J. Chem. Phys.</i> <b>125</b>, 164102 (2006).</p>
<p class="p3"><i>for questions or comments contact</i></p>
<p class="p3">Randall B. Shirts<span class="s2"><br>
</span>Department of Chemistry and Biochemistry<span class="s2"><br>
</span>Brigham Young University<span class="s2"><br>
</span>Provo, UT 84602</p>
<h3 style="margin: 0.0px 0.0px 14.0px 0.0px; font: 12.0px Times; color: #001cc1"><span class="s3"><b>E-Mail Address:<span class="Apple-converted-space"> </span></b></span>randy_shirts@byu.edu</h3>
<h3 style="margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times; color: #001cc1"><b>Office Telephone Number:<span class="Apple-converted-space"> </span></b><span class="s4">(801) 422-4290</span></h3>
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<h3 style="margin: 0.0px 0.0px 14.0px 0.0px; font: 12.0px Times; color: #001cc1"><span class="s3"><b>Office Room Number:<span class="Apple-converted-space"> </span></b></span>C312 BNSN, BYU campus</h3>
<p class="p2"><span class="s5">return to <a href="http://www.chem.byu.edu/index.php"><span class="s6">Department of Chemistry and Biochemistry homepage</span></a></span></p>
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