Quantum Monte Carlo study of ground and first excited state of C, N, O, F, and Ne atoms using Slater‐Jastrow‐Backflow wave function. Issue 11 (2nd March 2020)

• Record Type: Journal Article
• Authors: Nasiri, Saeed; Zahedi, Mansour
• Is Part Of: International journal of quantum chemistry. Volume 120:Issue 11(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-02
• Subjects: backflow transformation -- excited state -- ground state of C, N, O an F atoms -- quantum monte‐carlo -- Slater‐Jastrow; Quantum chemistry -- Periodicals; 541.28
• DOI: 10.1002/qua.26187
• Languages: English
• ISSNs: 0020-7608

Abstract

Abstract: All‐electron fixed‐node diffusion quantum Monte Carlo energies of the two lowest‐lying states of C, N, O, F, and Ne atoms are reported. The Slater‐Jastrow form is used as the trial wave function. We will use single‐ and multideterminant wave functions as the Slater part. The single‐determinant wave function has been computed by the Hartree‐Fock method and the multideterminant wave functions have been computed by the complete active space self‐consistent field, configuration interaction with single and double excitation, configuration interaction with single, double, triple, and quadruple excitation and second‐order configuration interaction. For the ground‐ and first excited states, the multideterminant wave functions have computed more than 99% of the correlation energy. Significant improvements have been achieved using the backflow transformations and up to 99.8% of the correlation energy has been recovered. A very good agreement with the experimental data has been obtained for the excitation energies. Abstract : In this paper highly accurate quantum mote‐carlo calculations have been performed using Slater‐Jastrow trial wave function for the two lowest‐lying states of C, N, O, F, and Ne atoms. Various wave functions have been used as the Slater part. The computed total energies are more accurate than previous reports and very good agreement with the experimental data has been obtained for the excitation energy.