Study of the low energy spectrum of titanium by using QMC methods

• Published in: Chemical physics letters Vol. 693; pp. 72 - 78
• Main Authors: Buendía, E., Caballero, M.A., Gálvez, F.J.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-02-2018
• Subjects: Electronic structure; Excitation energies; Explicitly correlated wave functions; Quantum Monte Carlo; Ti atom; Explicitly correlated wave functions; Quantum Monte Carlo; Electronic structure; Excitation energies; Ti atom
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2018.01.004

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•Study of the low energy spectrum of titanium.•Explicitly correlated wave functions are used to describe the states.•Calculations have been carried out by using QMC methods, variational and diffusion.•Static and dynamic correlations are needed to get a good agreement with experiments.
We study the ground state and the low energy excited states of Ti. Each variational wave function is a product of a Jastrow correlation factor by a model function obtained within the parameterized optimized effective potential (POEP) framework by using a configuration mixing. Near degeneracy effects between the orbitals 4s and 4p, as well as excitations to the 3d orbital due to the strong competition between 4s and 3d orbitals in transition metal atoms are taken into account. All electron calculations have been carried out by using quantum Monte Carlo techniques, variational and diffusion.