[cig-commits] [commit] master: Add entropy to debye (0e43ce6)

[cig_noreply at geodynamics.org]

Repository : https://github.com/geodynamics/burnman

On branch  : master
Link       : https://github.com/geodynamics/burnman/compare/e7f78ff83a8092bc07fea4398232e73406e7cbbb...6111717707e0bd07c31d999c20c7a56db163ff48

>---------------------------------------------------------------

commit 0e43ce63a1d513bbfc61496b17b3f09469643637
Author: ian-r-rose <ian.r.rose at gmail.com>
Date:   Fri Dec 12 13:50:27 2014 -0800

    Add entropy to debye


>---------------------------------------------------------------

0e43ce63a1d513bbfc61496b17b3f09469643637
 burnman/debye.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/burnman/debye.py b/burnman/debye.py
index b1fc227..c085abb 100644
--- a/burnman/debye.py
+++ b/burnman/debye.py
@@ -143,3 +143,13 @@ def helmholtz_free_energy(T, debye_T, n):
     F = n * constants.gas_constant * T * ( 3.0 * np.log( 1.0 - np.exp(-x)) - debye_fn_cheb(x) )
     return F
 
+def entropy( T, debye_T, n):
+    """
+    Entropy due to lattice vibrations in the Debye model [J/K]
+    """
+    if T <= eps:
+        return 0.
+    x = debye_T/T
+    S = n * constants.gas_constant * ( 4. * debye_fn_cheb(x) - 3. * np.log( 1.0 - np.exp(-x) ) ) 
+    return S
+