Research On Cd â…  Energy Spectrum By Multichannel Quantum Defect Theory

Nowadays, mankind has already come into an age of knowledge economy and information, and materials science has become one of the best developed subjucts in modern science and technology. Modern analysis method of materials, as a kind of research means, plays an very important role in materials science research, especially presenting in its function and significance. Atomic spectrum analysis method is one of the most familiar and practical methods in numerous modern analysis methods of materials. Firstly, an introduction about the basic method of modern analysis method of materials is given in this thesis, then a presentation of the multichannel quantum defect theory(abr. MQDT) in atomic spectrum theory is also given, and the existing experimental energy levels and lifetimes of atom cadmium are analyzed by means of this theory. The main work of this thesis is that the MQDT models of Cd I even-parity J=1 and J=2 are analyzed, and a general calculation method about lifetimes of high excited state by wave function of MQDT is obtained. Two results as follows can begained by theoretical calculation:1.For the energy spectrum of Cd I even-parity J=1, a model having one ionizationlimit and two channels is adopted, and its MQDT parameters is obtained by fitting experimental spectrum data. The total 30 energy levels and lifetimes≤36) are got from calculation, and 20 new energy levels and 28 new lifetimes of this series' Rydberg state are predicted, then the fitted formula of its lifetimes is given as follows: τ = 0.8980v_n^2.755 .At the same time, the total 30 energy levels and lifetimes of5snd1/2[3/2](6≤n≤35) are also got from calculation, and 18 new energy levels and 26 new lifetimes of this series' Rydberg state are predicted, then the fitted formula of its lifetimes is given as follows: τ = 0.3628v_n^2.829. Finally, the two channel mixing coefficient of Cd I even-parity J=1 from calculation is given, while the interferencesituation of this two channels is analyzed.2.As before, for the energy spectrum of Cd I even-parity J-2, a similar model is adopted, and its MQDT parameters is obtained by fitting experimental spectrum data likewise. The total 30 energy levels and lifetimes of 5sra/y[y]2 (6^?^35) are got fromcalculation, and 16 new energy levels and 26 new lifetimes of this series' Rydberg state are predicted, then the fitted formula of its lifetimes is given as follows:r = 0.3963 vnzm. Meanwhile, the total 30 energy levels and lifetimes of 5sra/y[y]2 (6^?^35) are also got from calculation. Finally, the two channel mixing coefficient of Cd I even-parity J-2 from calculation is given, while the interference situation of this two channels is also analyzed.The main achievements of the research are: firstly, for the energy spectrum of Cd I even-parity J—\,2 has been analyzed and calculated by MQDT for the first time. Secondly, the theoretical calculation values are well matched up to existing experimental spectrum data. At last, more than 160 energy levels and lifetimes not given in experimental spectrum data have been predicted, which are very helpful in theoretical directions to those who undertake a research for Cd I's atomic spectrum.