Zobrazeno 1 - 10
of 481
pro vyhledávání: '"Helgaker, P."'
Non-adiabatic coupling matrix elements (NACMEs) are important in quantum chemistry, particularly for molecular dynamics methods such as surface hopping. However, NACMEs are gauge dependent. This presents a difficulty for their calculation in general,
Externí odkaz:
http://arxiv.org/abs/2407.14607
Autor:
Laestadius, Andre, Csirik, Mihály A., Penz, Markus, Tancogne-Dejean, Nicolas, Ruggenthaler, Michael, Rubio, Angel, Helgaker, Trygve
Publikováno v:
J. Chem. Phys. 160, 084115 (2024)
The exchange-only virial relation due to Levy and Perdew is revisited. Invoking the adiabatic connection, we introduce the exchange energy in terms of the right-derivative of the universal density functional w.r.t. the coupling strength $\lambda$ at
Externí odkaz:
http://arxiv.org/abs/2310.19144
Ab initio molecular dynamics in a magnetic field requires solving equations of motion with velocity-dependent forces -- namely, the Lorentz force arising from the nuclear charges moving in a magnetic field and the Berry force arising from the shieldi
Externí odkaz:
http://arxiv.org/abs/2306.08332
The Born-Oppenheimer (BO) approximation is less accurate in the presence of a strong magnetic field than in the absence of a field. This is due to the complicated and unpredictable response of electronic structure to the field, especially in the mixe
Externí odkaz:
http://arxiv.org/abs/2212.11040
A semiclassical theory of small oscillations is developed for nuclei that are subject to velocity-dependent forces in addition to the usual interatomic forces. When the velocity-dependent forces are due to a strong magnetic field, novel effects arise
Externí odkaz:
http://arxiv.org/abs/2212.10246
The Berry curvature is essential in Born$-$Oppenheimer molecular dynamics, describing the screening of the nuclei by the electrons in a magnetic field. Parts of the Berry curvature can be understood as the external magnetic field multiplied by an eff
Externí odkaz:
http://arxiv.org/abs/2211.07240
The Berry connection and curvature are key components of electronic structure calculations for atoms and molecules in magnetic fields. They ensure the correct translational behavior of the effective nuclear Hamiltonian and the correct center-of-mass
Externí odkaz:
http://arxiv.org/abs/2207.11004
Autor:
Helgaker, Trygve, Teale, Andrew M.
Lieb's convex formulation of density-functional theory is presented in a pedagogical manner, emphasizing its connection to Hohenberg-Kohn theory and to Levy's constrained-search theory. The Hohenberg-Kohn and Lieb variation principles are discussed,
Externí odkaz:
http://arxiv.org/abs/2204.12216
Publikováno v:
J. Chem. Phys. 156 044121 (2022)
The diagonal nonadiabatic term arising from the Born--Oppenheimer wave-function ansatz contains contributions from a vector and scalar potential. The former is provably zero when the wave function can be taken to be real valued, and the latter, known
Externí odkaz:
http://arxiv.org/abs/2111.10251
Strong magnetic fields have a large impact on the dynamics of molecules. In addition to the changes of the electronic structure, the nuclei are exposed to the Lorentz force with the magnetic field being screened by the electrons. In this work, we exp
Externí odkaz:
http://arxiv.org/abs/2105.04225