Quantum defect complex

The spectrum of the Sun contains the absorption lines associated with the atomic spectrum of heavier elements such as Fe (Figure 4.2), which indicates that the Sun is a second-generation star formed from a stellar nebula containing many heavy nuclei. The atomic spectra of heavier atoms are more complex. The simple expression for the H atom spectrum needs to be modified to include a quantum defect but this is beyond the scope of this book. Atomic spectra are visible for all other elements in the same way as for H, including transitions in ionised species such as Ca2+ and Fe2+ (Figure 4.2). 

Formulae for calculating transition probabilities in both the LS and Jcl coupling schemes, within the context of the Relativistic Quantum Defect Orbital (RQDO) formalism, which yields one-electron functions, are given and applied to the complex atomic system Ar 11. The application of a given coupling scheme to the different energy levels dealt with is justified. 

Rydberg states, which are Feshbach resonance states. Their complex energies n, for a fixed angular momentum and labeled by the principal quantum number n, satisfy the Rydberg formula with a complex quantum defect l n + j-Yn/... 

The first difficulty is more fundamental, and suggests that, in complex cases, more information is needed to determine quantum defect parameters completely than is available in a set of experimental transition energies. 

In molecules, starting from a case (d) basis set, the part of the electronic energy that must be added corresponds to the energy difference between the states of different A due to the different Coulomb and exchange interactions with the core [see Section 3.3.2], a difference which can be expressed, like the example shown by Herzberg and Jungen (1972) for a p-complex, as a function of the difference between the quantum defects of a and 7r. 

Due to the external electric fields the ionization threshold of an atom is lowered from the field-free value, hi fact, all states become quasi-bound, as the electron can ionize by tunneling through the potential states. This process becomes important for states close to the classical ionization energy or above. The combination of the complex coordinate method with an R-matrix quantum-defect method is discussed for parallel magnetic and... 

Oscillator strengths and Einstein emission coefficients for several Rydberg radicals are reported. The Quantum Defect Orbital (QDO) method has been employed, and comparison is made with the results of more complex theorical procedures. 

Jun Jungen, Ch., Roche, A.L. Fine structure of the 4f complexes of ArH and KrH revisited Quantum defect theory used as a spectroscopic tool, J. Chem. Phys. 110 (1999) 10784-10791. 

The main hardware types offered by physics are mentioned, namely trapped ions (or trapped atoms), quantum dots, quantum optical cavities, rf superconducting quantum interference devices (SQUIDs) and nitrogen-vacancy (NV) defects on diamond. Some are important simply as a benchmark to evaluate the quality of the implementations offered by chemistry, whereas others might be combined with lanthanide complexes to produce heterogeneous quantum information processors which combine the advantages of different hardware types. 

Even when the composition range of a nonstoichiometric phase remains small, complex defect structures can occur. Both atomistic simulations and quantum mechanical calculations suggest that point defects tend to cluster. In many systems isolated point defects have been replaced by aggregates of point defects with a well-defined structure. These materials therefore contain a population of volume defects. 

---