如何计算键级

关键词：键级，Mayer键级

本教程针对AMS2019.3及之前的版本，AMS2020以后的版本请参考链接：计算MAYER键级、G-J键级、N-M键级

1，任务类型选择single point计算，参数参考“ADF参数设置详解”

2，ADFinput > Details > Userinput，在窗口中输入：

bondorder printall

默认显示大于0.2的键级，如果需要自定义阈值，例如0.0（所有原子之间的键级无论大小均列出）可以设置为：

bondorder printall tol=0.0

同时ADFinput > Details > Symmetry，将默认的Auto改为NOSYM。

3，计算完毕后，得到所有原子，两两之间的MAYER、G-J、N-M (1)、N-M (2)、N-M (3) (*)键级关系：

 -----------------------------------------------------------------------------------------------
                          DIST. [A]                   BOND-ORDERS
                                                  (THRESHOLD =  0.000 )
 -----------------------------------------------------------------------------------------------
                                      MAYER        G-J    N-M (1)    N-M (2)    N-M (3) (*)
 -----------------------------------------------------------------------------------------------
  C      1 - C      2     1.4005     1.2389     1.4344     1.4936     1.4415     1.5643
  C      1 - C      3     2.4257    -0.0243     0.0085     0.0089    -0.0294     0.0093
  C      1 - C      4     2.8009     0.0719     0.1189     0.1238     0.0845     0.1297
  C      1 - C      5     2.4257    -0.0243     0.0086     0.0089    -0.0294     0.0093
  C      1 - C      6     1.4005     1.2389     1.4344     1.4936     1.4415     1.5643
  C      1 - H      7     2.1458    -0.0258     0.0059     0.0063     0.0444     0.0058
  C      1 - H      8     3.3947     0.0047     0.0150     0.0159     0.0537     0.0147
  C      1 - H      9     3.8709     0.0014     0.0015     0.0016     0.0398     0.0015
  C      1 - H     10     3.3947     0.0047     0.0150     0.0159     0.0537     0.0147
  C      1 - H     11     2.1458    -0.0258     0.0059     0.0063     0.0444     0.0058
  C      1 - H     12     1.0800     1.0374     0.9198     0.9718     0.9873     0.9024
  C      2 - C      3     1.4005     1.2387     1.4338     1.4937     1.4408     1.5649
  C      2 - C      4     2.4257    -0.0245     0.0085     0.0089    -0.0300     0.0093
  C      2 - C      5     2.8009     0.0717     0.1190     0.1239     0.0839     0.1298
  C      2 - C      6     2.4257    -0.0244     0.0085     0.0089    -0.0301     0.0093
  C      2 - H      7     1.0700     1.0392     0.9189     0.9724     0.9883     0.9019
  C      2 - H      8     2.1458    -0.0258     0.0060     0.0063     0.0450     0.0059
  C      2 - H      9     3.3947     0.0047     0.0150     0.0159     0.0543     0.0147
  C      2 - H     10     3.8709     0.0014     0.0015     0.0016     0.0404     0.0015
  C      2 - H     11     3.3947     0.0046     0.0150     0.0159     0.0543     0.0147
  C      2 - H     12     2.1541    -0.0258     0.0059     0.0062     0.0444     0.0058
  C      3 - C      4     1.4005     1.2392     1.4341     1.4939     1.4411     1.5652
  C      3 - C      5     2.4257    -0.0244     0.0085     0.0089    -0.0300     0.0093
  C      3 - C      6     2.8009     0.0717     0.1190     0.1239     0.0839     0.1298
  C      3 - H      7     2.1458    -0.0259     0.0060     0.0063     0.0450     0.0059
  C      3 - H      8     1.0700     1.0397     0.9190     0.9724     0.9883     0.9020
 
………………………………

N-M(i)指Nalewajski-Mrozek键级的不同版本，G-J指Gopinathan-Jug键级。

N-M键级的定义，参考文献：

• R.F. Nalewajski, J. Mrozek and A. Michalak, Two-electron valence indices from the Kohn-Sham orbitals, International Journal of Quantum Chemistry 61, 589 (1997)
• M. Mitoraj, A. Michalak and T. Ziegler, A Combined Charge and Energy Decomposition Scheme for Bond Analysis, Journal of Chemical Theory and Computation 5, 962 (2009)
• R.F. Nalewajski and J. Mrozek, Modified valence indices from the two-particle density matrix, International Journal of Quantum Chemistry 51, 187 (1994)
• R.F. Nalewajski, J. Mrozek and A. Michalak, Exploring Bonding Patterns of Molecular Systems Using Quantum Mechanical Bond Multiplicities, Polish Journal of Chemistry 72, 1779 (1998)
• R.F. Nalewajski, J. Mrozek and G. Mazur, Quantum chemical valence indices from the one-determinantal difference approach, Canadian Journal of Chemistry 74, 1121 (1996)

G-J键级的定义，参考文献：

• M.S. Gopinathan and K. Jug, Valency. I. A quantum chemical definition and properties, Theoretica Chimica Acta 1983 63, 497 (1983)

Mayer键级的定义，参考文献：

• I. Mayer, Charge, bond order and valence in the ab inition SCF theory, Chemical Physics Letters 97, 270 (1983)