Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spinfree Hamiltonian
Methodologies beyond the Born–Oppenheimer (BO) approximation are nowadays important to explain high precision spectroscopic measurements. Most previous evaluations of the BO correction are, however, focused on lightelement molecules and based on a nonrelativistic Hamiltonian, so no information about the BO approximation (BOA) breakdown in heavyelement molecules is available. The present work is the first to investigate the BOA breakdown for the entire periodic table, by considering scalar relativistic effects in the Diagonal BO correction (DBOC). In closed shell atoms, the relativistic EDBOC scales as Z ^{1.25} and the nonrelativistic EDBOC scales as Z ^{1.17}, where Z is the atomic number. Hence, we found that EDBOC becomes larger in heavy element atoms and molecules, and the relativistic EDBOC increases faster than nonrelativistic EDBOC. We have further investigated the DBOC effects on properties such as potential energy curves, spectroscopic parameters, and various energetic properties. The DBOC effects for these properties are mostly affected by the lightest atom in the molecule. Furthermore, in X _{2} or XAt molecule (X = H, Li, Na, K, Rb, and Cs) the effect of DBOC systematically decreases when X becomes heavier but in HX molecules, the effect of DBOC seems relatively similar among all the molecules.
 Authors:

^{[1]};
^{[1]};
^{[2]};
^{[1]}
 Tokyo Metropolitan Univ., Tokyo (Japan)
 Iowa State Univ., Ames, IA (United States)
 Publication Date:
 Report Number(s):
 ISJ8976
Journal ID: ISSN 10895639
 Grant/Contract Number:
 AC0207CH11358
 Type:
 Accepted Manuscript
 Journal Name:
 Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory
 Additional Journal Information:
 Journal Volume: 120; Journal Issue: 13; Journal ID: ISSN 10895639
 Publisher:
 American Chemical Society
 Research Org:
 Ames Laboratory (AMES), Ames, IA (United States)
 Sponsoring Org:
 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC22)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
 OSTI Identifier:
 1254324
Imafuku, Yuji, Abe, Minori, Schmidt, Michael W., and Hada, Masahiko. Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spinfree Hamiltonian. United States: N. p.,
Web. doi:10.1021/acs.jpca.6b01507.
Imafuku, Yuji, Abe, Minori, Schmidt, Michael W., & Hada, Masahiko. Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spinfree Hamiltonian. United States. doi:10.1021/acs.jpca.6b01507.
Imafuku, Yuji, Abe, Minori, Schmidt, Michael W., and Hada, Masahiko. 2016.
"Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spinfree Hamiltonian". United States.
doi:10.1021/acs.jpca.6b01507. https://www.osti.gov/servlets/purl/1254324.
@article{osti_1254324,
title = {Heavy element effects in the diagonal Born–Oppenheimer correction within a relativistic spinfree Hamiltonian},
author = {Imafuku, Yuji and Abe, Minori and Schmidt, Michael W. and Hada, Masahiko},
abstractNote = {Methodologies beyond the Born–Oppenheimer (BO) approximation are nowadays important to explain high precision spectroscopic measurements. Most previous evaluations of the BO correction are, however, focused on lightelement molecules and based on a nonrelativistic Hamiltonian, so no information about the BO approximation (BOA) breakdown in heavyelement molecules is available. The present work is the first to investigate the BOA breakdown for the entire periodic table, by considering scalar relativistic effects in the Diagonal BO correction (DBOC). In closed shell atoms, the relativistic EDBOC scales as Z1.25 and the nonrelativistic EDBOC scales as Z1.17, where Z is the atomic number. Hence, we found that EDBOC becomes larger in heavy element atoms and molecules, and the relativistic EDBOC increases faster than nonrelativistic EDBOC. We have further investigated the DBOC effects on properties such as potential energy curves, spectroscopic parameters, and various energetic properties. The DBOC effects for these properties are mostly affected by the lightest atom in the molecule. Furthermore, in X2 or XAt molecule (X = H, Li, Na, K, Rb, and Cs) the effect of DBOC systematically decreases when X becomes heavier but in HX molecules, the effect of DBOC seems relatively similar among all the molecules.},
doi = {10.1021/acs.jpca.6b01507},
journal = {Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory},
number = 13,
volume = 120,
place = {United States},
year = {2016},
month = {3}
}