Isotope shift measurement of high-lying atomic levels by multi-step photoionization

A new technique has been developed to measure isotope shifts of high-lying atomic levels using multi-step photoionization. This technique has been demonstrated with the measurement of isotope shift between²³⁵U and²³⁸U isotopes in the energy level at 34372.992 cm⁻¹. The value of isotope shift thus measured matches well with the value reported in literature.