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Born–Oppenheimer and non-Born–Oppenheimer calculations with explicitly correlated gaussians
| Content Provider | Semantic Scholar |
|---|---|
| Author | Bubin, Sergiy |
| Copyright Year | 2017 |
| Abstract | High accuracy calculations of small quantum systems, such as few-electron atoms and molecules, remain a challenge for modern theoretical and computational approaches. Of particular importance are applications pertinent to high precision spectroscopy, measurements of fundamental constants, and nuclear properties, as well as the determination of the stability of weakly bound states. Accurate knowledge of target structure is also important for studying collisions involving atomic and molecular targets. The variational method in conjunction with explicitly correlated Gaussian (ECG) basis sets has been used for several decades to investigate quantum few-body systems of various natures [1, 2]. While being conceptually simple, it remains one of the most powerful and reliable tools to study bound and scattering states of systems containing 3-8 interacting particles. In this talk I will review our recent developments in this field and present calculations on various quantum few-body systems with Coulomb interaction. In particular I will talk about our benchmark calculations of ground and excited states of small atoms (Li, Be, B) that account for the finite-nuclear mass and leading-order relativistic and QED effects. I will also review our work on small molecular systems without assuming the Born-Oppenheimer approximation. In the case of molecules, due to the the difference in the masses of the electrons and nuclei the latter move considerably more slowly and their pair correlation functions have distinct features that are difficult to capture using the usual all-particle correlated Gaussians while maintaining an analytic integrability of all necessary matrix elements. It can be argued that a possible solution may lie in using complex ECGs. Several relevant examples will be presented along with the discussion of the issues that arise for triand more atomic molecules. Lastly, I will talk about the calculations of small positronic atoms, the determination of their stability, and positron-electron annihilation rates. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://atom.curtin.edu.au/isiac/Selected_talk_abstracts/Bubin_S.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
