Many methods are used to optimize possible ground state structures of PO、PO₂ with multi-basis set. It was found that DFT method is the most suitable for calculation of PO,PO₂. For PO free radical, M-S potential energy functional constants are calculated with 6-311G(3df). For PO₂ free radical, equilibrium structure, harmonic frequency, dissociation energy and force constant are calculated with 6-311+G(3df). Potential energy functions of PO₂ are derived from many-body expansion theory. It was pointed out that there is a saddle point in reaction kinetics O+PO→OPO, and a stable PO₂ molecule could be formed as O atom with energy surpassing 0.55 eV. A stable PO₂ molecule could be formed through two equivalent channels over barrier.

QCISD method is used to optimize possible ground-state structures of PCl and PCl₂ molecule with multiple basis sets. Dissociation energy, harmonic frequency and force constants are calculated with 6-311 + G (dr) and 6-311G (dr) basis sets, respectively. They agree with experimental observations well. Potential energy functions of PCl₂ are derived from many-body expansion theory. Potential energy curves verify structure characteristics and potential depth. Cl+ PCl and P + ClCl based on molecular reaction potential energy surface are discussed. It describes molecular reaction dynamics successfully.

Density functional theory B3LYP method is used to optimize ground-state structures of NF molecule,NF⁺ and NF^- molecule ions with 6-311+ +g(df,3pd),6-311g(3d,3p) and 6-311+ +g(3df,3pd) basis sets,respectively.Frequency and single-point energy scan for NF^X(X=-1,0,+1) are calculated.With the least-square method,spectral parameters (B_e,α_e,ω_e,ω_eχ_e) of NF molecule and NF⁺ ion ground state are fitting to Murrell-Sorbie functions.Calculated results are in good agreement with experiments.Spectral parameters (B_e,α_e,ω_e,ω_eχ_e) and force constants (f₂,f₃,f₄) of NF^- molecular ion ground state are shown.