Quantum Chemistry for Metastable Anions

The traditional quantum chemistry methods discussed up to this point are designed to find the lowest Born-Oppenheimer energy and wave function (or density) for a given arrangement of the nuclei. For the AB system described 

The remainder of this section is devoted to methods that can get such systems right. As mentioned in the introductory remarks to this chapter, the discussion here is limited to methods that are based on relatively 

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Finally, this chapter covers not just bound-state methods but also methods that can safely be applied to metastable anions (i.e., temporary anion resonances), which is a far less mainstream topic. For metastable anions, the emphasis of this chapter is on those methods that have been implemented in standard quantum chemistry codes and are therefore widely available to the chemistry community. 

While CCSD(T), MP2, DFT, and so on are appropriate for bound anions, theoretical description of metastable anions requires specialized techniques. Many of these techniques are well-established but have seen far less use as compared to bound-state quantum chemistry. In this chapter, we have discussed a variety of techniques (the maximum overlap method, CCR, and stabilization methods) that are all based, at some level, on modifications to bound-state quantum chemistry that can be implemented as reasonably straightforward modifications of standard bound-state quantum chemistry codes. It is this author s hope that this review of such methods for temporary anion resonances will prompt renewed and increased interest in these techniques. 

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