An electronic Hamiltonian for origin independent calculations of magnetic properties

Abstract

A gauge origin independent formalism for the calculation of molecular magnetic properties is presented. Origin independence is obtained by using London’s gauge invariant atomic orbitals, expanding the second quantization Hamiltonian in the external magnetic field and nuclear magnetic moments, and using the resulting expansion terms as perturbation operators in response function calculations. To ensure orthonormality of the molecular orbitals, a field-dependent symmetrical orthonormalization is employed. In this way the gauge dependence of the London orbitals is transferred to the Hamiltonian. The resulting perturbation operators may be used to calculate magnetic properties from any approximate ab initio wave function.

Intrinsic Optical Activity and Large-Amplitude Displacement: Conformational Flexibility in (R)-Glycidyl Methyl Ether

“…Densityfunctional chiroptical calculations employed the dipole-length gauge (LG) in conjunction with gauge-including atomic orbitals 11,43 (GIAOs) to ensure translational invariance. Because conventional coupled-cluster schemes cannot benefit from this approach, attendant linear-response predictions were performed in both the dipole-length (LG) and dipole-velocity (VG) gauges, 44 where the latter should mitigate the nonphysical dependence of the former on the position of the coordinate origin (which was fixed at the molecular center of mass).…”

Shedding light on the photophysical properties of newly designed platinum(II) complexes by adding substituents on functionalized ligands as highly efficient OLED emitters from a theoretical viewpoint

“…Four different DFT functionals, namely, B3LYP [21,22], PBE0 [23], M06-2X [24], and CAM-B3LYP [25] were employed to calculate the absorption spectra for three reported complexes Pt-1, Pt-2, and Pt-3. As compared with the experimental results, the TD-B3LYP method [26,27] was applied to investigate the absorption spectral properties associated with the polarized continuum model (PCM) [28,29] in tetrahydrofuran (THF) media and the T n / S 0 emission spectra in gas state on the basis of the respective equilibrium geometries of ground and excited states. As regards the basis set, the "double-z" quality basis set consisting of Hay and Wadt's effective core potentials (LANL2DZ) [30,31] was employed for the Pt atom and 6-31G(d) [32] for all the non-metal atoms.…”

DFT/TDDFT investigation on the electronic structures and photophysical properties of phosphorescent platinum(II) complexes with triarylboron/triarylnitrogen-functionalized N-heterocyclic carbene chelate ligands

“…Besides, single point calculations were performed at the optimized ground state geometries of these complexes for the molecule orbital population. On the basis of the optimized structures of the ground and excited states, the absorption and emission properties in dichloromethane (CH 2 Cl 2 ) medium were calculated by timedependent density functional theory (TDDFT) [27,28] associated with the polarized continuum model (PCM) [29,30]. Meanwhile, five different density functional (M052X [31], M062X [32], BP86 [33], B3LYP [34,35] and PBE0) were performed to calculate the emission spectra for 1a and 2a, aimed at finding the method that would allow for the reliable prediction of emission properties.…”