Systematical study on the ionization potential of excited states in carbon-like sequence

Ionization potential of excited states have been calculated for the 1s22s22p2 3P2, 1s22s22p3s 3P02, 1s22s22p3d 3D03, 1s22s22p3d 1F03, and 1s22s22p4d 3D03 series of carbon-like sequence from Z=6 to Z=23 on the basis of the weakest bound electron potential model theory and the concept of iso-spectrum-level series. In the calculation, the non-relativistic weakest bound electron potential model theory is used to calculate the non-relativistic energies and a fourth-order polynomial in nuclear charge Z is employed to evaluate the relativistic correction. Calculated values are compared with the experimental compiled results. Agreement with the experimental compiled results is generally within 0.1%.