Radiative Transitions between the $4D^{10}5p^2{(}^3{P}_j)nl$ and $4D^{10}5s5p{(}^3{P}_1^o)nl$ Autoionizing States of in Atom in Collisions of Slow Electrons with in${}^{+}$ Ions

Abstract

The radiative transitions between the $4d^{10}5p^2{(}^3{P}_{0,1,2})nl$ and {$4d^{10}5s5p({}^3{P}_1^o)nl$ autoionizing} states of an indium atom that represent dielectronic satellites of the $4d^{10}5p^2{}^3{P}_0\to 4d^{10}5s5p{}^3{P}_1$ ($\lambda =171.7$ nm), $4d^{10}5p^2{}^3{P}_1\to 4d^{10}5s5p{}^3{P}_1$ ($\lambda =166.7$ nm), and $4d^{10}5p^2{}^3{P}_2\to 4d^{10}5s5p{}^3{P}_1$ ($\lambda =160.7$ nm) spectral lines of an In${}^{+}$ ion have been observed for the first time. The energy dependences of the effective excitation cross sections of dielectronic satellites, as well as near-threshold regions of these spectral lines, were investigated in the range of electron energies 9$÷$15 eV with the help of the spectroscopic method using crossed beams of electrons and In${}^{+}$ ions. The absolute excitation cross sections of dielectronic satellites amount to $(0.7÷2)\times 10^{-16}$ cm${}^2$ and are of the same order of magnitude as the effective excitation cross sections of the corresponding ionic lines. It is found that a considerable increase of the probability of radiation decay of the $4d^{10}5p^2{(}^3{P}_{0,1,2})nl$ autoionizing states of the In atom is related to strong relativistic and correlation effects, in particular to the configuration interaction of the $5p^{2}nl$ levels both with one another and with the levels of the $5s5dnl$ and $4d^{9}5s^{2}5p^2$ configurations.