Current‐density functional study of the HeH⁺ molecular ion under a strong ultrashort magnetic field

Abstract

VikasThe HeH þ molecular ion under an ultrashort magnetic field on the order of 10 9 G is investigated through quantum fluid dynamics and a current-density functional theory (CDFT) based approach, employing a vector exchange-correlation (XC) potential which depends on the electronic charge-density as well as on the current-density. The behavior of the exchange and correlation energies of the HeH þ ion is analyzed and compared with those obtained using an approach based on the time-dependent density functional theory (TD-DFT) under similar computational constraints but employing a scalar XC potential dependent only on the electronic chargedensity. The CDFT-based approach yields exchange and correlation energies as well as TD electronic charge-densities drastically different from those obtained using the TD-DFTbased approach particularly, at typical TD magnetic field strengths. This is attributed to the nonadiabatic effects induced by the vector XC potential of the CDFT in the oscillating charge-density of the HeH þ ion, which are further explained in the terminology of quantum fluid dynamics. The vector XC potential of the CDFT-based approach is observed to augment the magnetic interactions in the H 2 molecule and in the He 2þ 2 ion, whereas it opposes the magnetic interactions in the HeH þ ion particularly, at the intermediate magnetic field strengths.

DFT calculations of atoms and molecules in Cartesian grids

“…This procedure has been successfully applied to a variety of interesting static and dynamic many-electron situations. Some of these are electronic structure calculations [59], ion-atom collisions [60,61], atoms, molecules in presence of strong TD electric and/or magnetic fields [62][63][64][65][66][67] including high-harmonic generation and multi-photon ionization, etc. Many more details could be found in the above references and therein.…”

The influence of benzene rings on aromatic pathways in the porphyrins

“…It should be noted that the density functional theory (DFT), where B3LYP exchange‐correlation (XC) functional does not depend on the current‐density, is used in the works . However, in the presence of a magnetic field, the XC functional also becomes dependent on the current‐density, and in such situations, current‐DFT (CDFT) is most appropriate . At same time, CDFT is still insufficiently developed for application to large‐size molecules.…”