2 research outputs found
Spin-Phonon Coupling and Dynamic Zero-Field Splitting Contributions to Spin Conversion Processes in Iron(II) Complexes
Magnetization dynamics of transition metal complexes manifest in properties and phenomena of fundamental and applied interest [e.g., slow magnetic relaxation in single molecule magnets, quantum coherence in quantum bits (qubits), and intersystem crossing (ISC) rates in photophysics]. While spin–phonon coupling is recognized as an important determinant of these dynamics, additional fundamental studies are required to unravel the nature of the coupling and, thus, leverage it in molecular engineering approaches. To this end, we describe here a combined ligand field theory and multireference ab initio model to define spin–phonon coupling terms in S = 2 transition metal complexes and demonstrate how couplings originate from both the static and dynamic properties of ground and excited states. By extending concepts to spin conversion processes, ligand field dynamics manifest in the evolution of the excited state origins of zero-field splitting (ZFS) along specific normal mode potential energy surfaces. Dynamic ZFSs provide a powerful means to independently evaluate contributions from spin-allowed and/or spin-forbidden excited states to spin–phonon coupling terms. Furthermore, ratios between various intramolecular coupling terms for a given mode drive spin conversion processes in transition metal complexes and can be used to analyze the mechanisms of ISC. Variations in geometric structure strongly influence the relative intramolecular linear spin–phonon coupling terms and will define the overall spin state dynamics. While the findings of this study are of general importance for understanding magnetization dynamics, they also link the phenomenon of spin–phonon coupling across fields of single molecule magnetism, quantum materials/qubits, and transition metal photophysics
OGLE-2018-BLG-0532Lb: Cold Neptune With Possible Jovian Sibling
We report the discovery of the planet OGLE-2018-BLG-0532Lb, with very obvious
signatures in the light curve that lead to an estimate of the planet-host mass
ratio . Although there are
no obvious systematic residuals to this double-lens/single-source (2L1S) fit,
we find that can be significantly improved by adding either a third
lens (3L1S, ) or second source (2L2S, ) to
the lens-source geometry. After thorough investigation, we conclude that we
cannot decisively distinguish between these two scenarios and therefore focus
on the robustly-detected planet. However, given the possible presence of a
second planet, we investigate to what degree and with what probability such
additional planets may affect seemingly single-planet light curves. Our best
estimates for the properties of the lens star and the secure planet are: a host
mass , system distance kpc and planet mass
with projected separation au.
However, there is a relatively bright (and also relatively blue) star
projected within mas of the lens, and if future high-resolution images
show that this is coincident with the lens, then it is possible that it is the
lens, in which case, the lens would be both more massive and more distant than
the best-estimated values above.Comment: 48 pages, 9 figures, 7 table