Theoretical Study Of Energies, Radiative And Auger Decay Processes On Core-excited States Of Highly-ionized Ions

In this work, Wavefunctions, energies, radiative decay possibilities and non-radiative(Auger) decay rates of the core-excited and doubly-excited states of highly-ionized ions arestudied by a fully relativistic MCDF method and the relevant atomic structure packageGRASP92and RATIP. The effect of electron correlation on energy levels, radiative decaypossibilities and non-radiative decay rates are discussed in detail. Variation of the radiativedecay possibilities and non-radiative decay rates with increasing Z are studied. Effects ofthe finite nuclear size, Breit effect, QED effect (including transverse photon interaction andvacuum polarization) are also considered to make the results more precise. Following arethe main contents and results of this work specifically.1. Wavefunctions, energies, radiative decay possibilities and non-radiative (Auger)decay rates of the core-excited1s(2l2l′)3are studied. Effect of electron correlation onenergy levels of core-excited states1s2p3are investigated. Results show that electroncorrelations effects are very important for energies and radiative decay rates of core-excitedstates in BII and that both the valence-valence and core-valence electron correlations needto be considered in the calculations. Auger decay rates of quintuplet1s2p35S2states and1s2s2p25P1,5P2,5P3states are much smaller compared to these of other states, whichimplies that these states are more stable than the other states in this work. Auger branchratios to different limits are discussed. We found that the Auger branch ratio is smallerwhen the angular quantum number of the electron who jump down to the lower state ischanged than the angular quantum number not changed. Good agreement are foundbetween our results and others from experiments and theoretical calculations.2. Energies, radiative decay rates and Auger decay probabilities of the core-excitedstates1s(2l2l′)3of Be-like ions for Z=8-28are studied. Electron correlations effects areconsidered using active space method in extended optimal level mode. Results show thatradiative rates increase smoothly with increasing Z in the Z space from8to28because ofrelativistic effect. Auger rate changes not so significantly as radiative rates. At low Z,Auger rates is greater than radiative probabilities, while at Z=28, for most of the states, radiative probabilities exceed the Auger rates. Auger BR to1s22l (1s22s and1s22p) and1s23l (1s23s,1s23p and1s23d) limits are also investigated in this work. BR to1s23l limitsare almost zero, except for ions at Z=8and10because of electron correlation effect. Augerand radiative decay rates of quintet states5P1,2,3are much smaller than other states, whichmeans that these states are stable than other states.3. Energy and kα radiative transition processes of C-like to F-like Al ions arestudied where radiative transition rates, energies and spectra are included. Electroncorrelation effects on the energy and radiative rates are discussed in detail. For thecore-excited and the ground states in this work, electron correlation effect is caused mainlyby correlation between the valent electrons. Influences of electron correlation on levelenergies get bigger in general as the number of extranuclear electrons increasing along theAl ions system. The influence of electron correlation effect on radiative transition rates isreflected on the agreement of results from Coulomb gauge and Babushkin gauge. Ourresults of kα transition spectrum agree well with recent experimental results.4. Energy levels, Auger decay and radiative transition rates of the doubly-excited1s23l3l′states for Be-like neon are calculated. Electron correlation and relaxation effects aretaken into account. The magnitude of Auger rates for the35doubly-excited states1s23l3l′and their decay channels are discussed. Our results show that the magnitudes of the Augerrates in this system are larger for these initial states whose energies are closer to thethreshold. For the same dominant configuration, the total Auger decay probabilities for theinitial singlet states are larger than those of the initial triplet states. It can be explained thattwo excited electrons with antiparallel spin in the initial singlet state have strongerinteraction. Comparing to Auger rates, radiative probabilities are weaker by2-4orders ofmagnitude. This implies that the Auger decay is far stronger than the radiative decay forthis system. Our results agree well with recent experimental and other theoretical results.Highly-ionized ions in core-excited states widely exist in celestial body andexperimental plasma. The studies on highly-ionized ions on core-excited states andhighly-doubly-excited states is important for astrophysics, plasma physics and otherrelevant field of science, and it is one of the study focuses of atomic physics. The studies onhighly-ionized ions on core-excited states and highly-doubly-excited states can help analyse the detailed process in plasmas, can help identify kinds of experimental spectra. Meanwhile,it can provide theoretical supports to further experimental researches. Exact studies onhighly-ionized ions on core-excited states and highly-doubly-excited states are of importantresearch value.