1.Please use ChatGPT to explore the two questions about computational chemistry knowledge ( except homework )

2.Use Gaussian、 Spartan or WebMO to calculate the ionization energy of atoms with atomic number 1~18, by using HF、B3LYP and MP2 theoretical methods with 6-31G** and 6-311G** basis set, and do some simple statistical analysis.

experimental value ref: Computational Chemistry Comparison and Benchmark DataBase

(Unit: eV) 

This bar chart tells us under the same basis set, HF gives the most deviation from the exp values and B3LYP is the best method among the three.