Reevaluation of term isotope shifts of low even levels of 4f86s2 configuration and high odd-parity levels of neutral gadolinium atoms

Isotope shift ΔT(156Gd–160Gd) of the even-parity energy levels of 4f86s2 and 4f76s26p configurations of neutral gadolinium atoms (Gd I) have been reevaluated using the level isotope shift (ΔT) of two odd-parity levels reported recently. Earlier the isotope shifts of these even-parity energy levels were evaluated using empirical relation. Our extensive isotope shift data has been used for the reevaluation of ΔT values of these low even-parity energy levels which have been utilised for revision of the ΔT values of high-lying odd-parity energy levels of Gd I.