王昱喬-第八週作業

Plot potential energy curve of H2 + H → H + H2 reaction

  • Use Gaussian to find the potential energy of H2 + H → H + H2.
  • Collect data from the output file and use OriginPro 9 to plot the potential energy curve(2D).
  • Data Link : Google Drive

1 2 3

SC1=bond length between H1 & H2 

SC2=bond length between H2 & H3

Unit=Angstroms

5 4

 

Calculate the structures and atomization energies (AE) of AHn (A = H~Ne) with the following method then compare with the experimental values.

  • Calculate the atomization energies by calculating A & AHn in Gaussian.
  • Collect all data from the output file and use the function [A(EE)+H(EE)*n-AHn(EE)]*627.5095 ( kcal/mol ) to calculate the atomization energies (AE).
  • Find the Bond length (Å) & Bond angle (degree) in the output file too.
  1. Calculate the atomization energies (AE) by following methods/basis set

         optimization

         MP2/6-31+G(d,p)

         MP2/aug-cc-pVTZ

         B3LYP/6-31+G(d,p)

         B3LYP/aug-cc-pVTZ

        single point energy

        CCSD(T)/aug-cc-pVTZ

 

unit=kcal/mol 

Atomization energies of hydrides
　 MP2/6-31+G(d,p) MP2/aug-cc-pVTZ B3LYP/6-31+G(d,p) B3LYP/aug-cc-pVTZ Experimental value(D0)
H2 101.2 103.8 111.7 110.1 103.3
LiH 45.2 51.8 57.2 58.5 55.7
BeH2 141.0 146.0 155.7 155.3 149.3
BH3 269.5 275.5 286.7 284.7 266.8
CH4 399.4 411.4 422.8 420.6 392.4
NH3 274.9 290.2 300.2 300.7 276.7
H2O 220.5 232.2 229.6 230.6 219.4
HF 137.3 143.7 138.4 139.1 135.4

 

Atomization energies of hydrides
　 MP2/6-31+G(d,p) MP2/aug-cc-pVTZ B3LYP/6-31+G(d,p) B3LYP/aug-cc-pVTZ
H2 2.1 0.5 8.4 6.8
LiH 10.5 3.9 1.5 2.8
BeH2 8.3 3.3 6.4 6.0
BH3 2.7 8.7 19.9 17.9
CH4 7.0 19.0 30.4 28.2
NH3 1.8 13.5 23.5 24.0
H2O 1.1 12.8 10.2 11.2
HF 1.9 8.3 3.0 3.7
絕對誤差平均值 4.4 8.7 12.9 12.6

 

Atomization energies of hydrides
　 CCSD(T)/aug-cc-pVTZ//MP2/6-31+G(d,p) CCSD(T)/aug-cc-pVTZ//B3LYP/6-31+G(d,p) CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ Experimental value(D0)
H2 108.5 108.6 108.5 108.6 103.3
LiH 56.9 56.9 56.9 56.9 55.7
BeH2 145.1 145.1 145.1 145.1 149.3
BH3 276.8 276.8 276.8 276.8 266.8
CH4 428.0 428.0 428.0 428.0 392.4
NH3 291.2 291.2 291.3 291.3 276.7
H2O 228.2 228.2 228.2 228.2 219.4
HF 139.2 139.2 139.3 139.3 135.4

 

Atomization energies of hydrides
　 CCSD(T)/aug-cc-pVTZ//MP2/6-31+G(d,p) CCSD(T)/aug-cc-pVTZ//B3LYP/6-31+G(d,p) CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ CCSD(T)/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ
H2 5.2 5.3 5.2 5.3
LiH 1.2 1.2 1.2 1.2
BeH2 4.2 4.2 4.2 4.2
BH3 10.0 10.0 10.0 10.0
CH4 35.6 35.6 35.6 35.6
NH3 14.5 14.5 14.6 14.6
H2O 8.8 8.8 8.8 8.8
HF 3.8 3.8 3.9 3.9
絕對誤差平均值 10.4 10.4 10.4 10.4

experimental value:Computational Chemistry Comparison and Benchmark DataBase

1 2 

3 4

5 6

 

 

  2. Calculate the structure 

Bond angle ( degree )
　 MP2/6-31+G(d,p) MP2/aug-cc-pVTZ B3LYP/6-31+G(d,p) B3LYP/aug-cc-pVTZ Exp
H2 - - - - -
LiH - - - - -
BeH2 180.0 180.0 180.0 180.0 180.0
BH3 120.0 120.0 120.0 120.0 120.0
CH4 109.5 109.5 109.5 109.5 109.5
NH3 108.1 106.8 108.1 107.2 106.7
H2O 105.4 104.1 105.8 105.1 104.5
HF - - - - - 

 

 

Bond length (Å)
　 MP2/6-31+G(d,p) MP2/aug-cc-pVTZ B3LYP/6-31+G(d,p) B3LYP/aug-cc-pVTZ Exp
H2 0.734 0.737 0.743 0.743 0.741
LiH 1.623 1.605 1.614 1.590 1.595
BeH2 1.328 1.330 1.331 1.325 1.326
BH3 1.186 1.187 1.193 1.188 1.190
CH4 1.087 1.086 1.093 1.088 1.087
NH3 1.012 1.012 1.016 1.013 1.012
H2O 0.963 0.961 0.965 0.962 0.958
HF 0.926 0.922 0.928 0.924 0.917

 

Absolute error of bond length (Å)
　 MP2/6-31+G(d,p) MP2/aug-cc-pVTZ B3LYP/6-31+G(d,p) B3LYP/aug-cc-pVTZ
H2 0.007 0.004 0.002 0.002
LiH 0.028 0.010 0.019 0.005
BeH2 0.002 0.004 0.005 0.001
BH3 0.004 0.003 0.003 0.002
CH4 0.000 0.001 0.006 0.001
NH3 0.000 0.000 0.004 0.001
H2O 0.005 0.003 0.007 0.004
HF 0.009 0.005 0.011 0.007
絕對平均誤差 0.007 0.004 0.007 0.003

   

Conclusion

  • when the molecule contains more hydrogen atoms, the absolute error is larger