非周期性自由能的计算

由于AMS统一了各个模块的算法，因此ReaxFF计算自由能与ADF计算自由能的方式是一样的，输出内容也非常相似。计算反应过程中，涉及反应的少数分子的自由能，应该去掉周期性（Periodicity选择None）。

本文以ReaxFF作为范例，其他模块例如机器学习势、DFTB、BAND模块，除了Main的参数设置不同，其他设置完全一致。

选择力场，去掉周期性： 设定温度、压强：

提交作业。

SCM - Output - Other Properties - Statistical Thermal Analysis:

 Pressure:                  1.000000 atm.
 Temperature:            1298.150000 K



 Moments of Inertia [amu*bohr^2] and principal axis
 ==================================================

          61.4910        440.7143        501.5491
 ------------------------------------------------
           0.1033         -0.2326         -0.9671
           0.9806         -0.1389          0.1382
           0.1664          0.9626         -0.2138


 The rotational contribution to the molecular entropy includes
 a term, dependent on the symmetry number sigma. The results 
 reported below were computed using sigma = 1, determined from
 the point group symmetry of the input geometry (NOSYM). 
 If this is not the correct symmetry, try symmetrizing the molecule before
 running the calculation (note: linear molecules should be aligned along one
 of the Cartesian axes).
 Contributions from frequencies below 20 1/cm are not included in vibrational sums.
 Their contributions, if any, are reported separately.


     Temp                                                        Transl      Rotat     Vibrat     Total
     ----                                                        ------      -----     ------     -----

    1298.15   Entropy (cal/mol-K):                               45.503     28.508     15.601     89.612
              Nuclear Internal Energy (kcal/mol):                 3.870      3.870     17.607     25.346
              Constant Volume Heat Capacity (cal/mol-K):          2.981      2.981     10.475     16.437
          (c) Constant Volume Heat Capacity (cal/mol-K):          2.981      2.981     10.187     16.148

       Summary of energy terms
                                                   hartree              eV         kcal/mol           kJ/mol
                                      --------------------     -----------       ----------      -----------
      Energy from Engine:               -0.422705614065143        -11.5024          -265.25         -1109.81
      Nuclear Internal Energy:           0.040391413339248          1.0991            25.35           106.05
  (c) Nuclear Internal Energy:           0.039790671912575          1.0828            24.97           104.47
      Internal Energy U:                -0.382314200725895        -10.4033          -239.91         -1003.77
      pV/n = RT:                         0.004111001420113          0.1119             2.58            10.79
      Enthalpy H:                       -0.378203199305783        -10.2914          -237.33          -992.97
      -T*S:                             -0.185382594459980         -5.0445          -116.33          -486.72
  (c) -T*S:                             -0.184292084586826         -5.0148          -115.65          -483.86
      Gibbs free energy:                -0.563585793765762        -15.3359          -353.66         -1479.69

可以看到Gibbs 自由能为-353.66 kcal/mol