Polarization Energy for3dand4pElectrons

Meshkov has demonstrated the presence of an appreciable polarization energy associated with the combination of a $3d$ and a $4p$ electron in the $3d^{2}4p$ configuration of Ti ii. He has shown that the mean deviation between theory and experiment is reduced from ±332 K to ±249 K when this energy is considered. It is here noted that by use of a modified form of Meshkov's approximation a further reduction to ±180 K is produced. This modification requires only three adjustable parameters, as compared with the five required in Meshkov's original method. It is suggested that the agreement could be made even better if a breakdown of $\mathrm{LS}$-coupling due to the closeness of three terms in this spectrum were considered.