Use Spartan or WebMO to calculate the electron affinity of atoms with atomic number 1~10, by using CCSD(T)、B3LYP and MP2 theories with d-aug-cc-pVTZ basis sets and add an S orbital and an P orbital diffuse functions to the 6-31++G(d,p) basis set, and do some simple statistical analysis

Data link:Google Drive

electron affinity & mean absolute error ( unit: kcal/mol )

1, use basis set with add an S orbital and an P orbital diffuse functions to 6-31++G(d,p) for different theories

	H	He	Li	Be	B	C	N	O	F	Ne	MAE
MP2/6-31++G(d,p)	-3.0	127.9	-5.7	15.3	1.2	-22.7	20.1	-25.1	-78.5	172.0	36.4
B3LYP/6-31++G(d,p)	-20.5	117.4	-12.6	5.3	-9.6	-31.4	-3.2	-37.4	-81.0	157.6	28.8
CCSD(T)/6-31++G(d,p)	-17.1	13.1	-14.2	7.4	-5.5	-28.2	5.2	-31.2	-76.7	32.9	4.5
experimental value	-17.4	5.0	-14.3	4.3	-5.5	-29.1	1.7	-33.7	-77.0	6.9

2, use basis set d-aug-cc-pVTZ for different theories

	H	He	Li	Be	B	C	N	O	F	Ne	MAE
MP2/d-aug-cc-pVTZ	-10.4	13.2	-8.1	8.2	-4.9	-29.2	17.3	-33.0	-84.2	33.4	7.6
B3LYP/d-aug-cc-pVTZ	-21.4	10.1	-12.8	1.0	-11.8	-32.1	-8.4	-39.3	-81.7	28.4	6.5
CCSD(T)/d-aug-cc-pVTZ	-17.1	13.1	-14.2	7.4	-5.5	-28.2	5.2	-31.2	-76.7	32.9	4.5
experimental value	-17.4	5.0	-14.3	4.3	-5.5	-29.1	1.7	-33.7	-77.0	6.9

experimental value website: Computational Chemistry Comparison and Benchmark DataBase

Organize the calculated data of ionization energy, and compare it with the experimental value

  

   

  

Plot the eletron density of He and He+ like the figure below.

Electron Density: e/Bohr³   

   

   

• Conclusion

1.After we add additional diffuse function, it can help us reduce the error of Helium and Neon atom.