Ionization potentials and quantum defects of 1s²np²P rydberg states of lithium atom

In this work, ionization potentials and quantum effects of 1s ²np²P Rydberg states of lithium are calculated based on the calibrated quantum defect function. Energy levels and quantum defects for 1s²np²P bound states and their adjacent continuum states are calculated with the R-matrix theory, and then the quantum defect function of the 1s²np (n ≥ 7) channel is obtained, which varies smoothly with the energy based on the quantum defect theory. The accurate quantum defect of the 1s²7p²P state derived from the experimental data is used to calibrate the original quantum defect function. The new function is used to calculate ionization potentials and quantum effects of 1s²np ²P (n ≥ 7) Rydberg states. Present calculations are in agreement with recent experimental data in whole.