Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2108.13337

Clock Transitions Guard Against Spin Decoherence in Singlet Fission

Sina G. Lewis·Kori E. Smyser·Joel D. Eaves
View original source ↗Read source document ↗Export metadata ↓

Abstract

Short coherence times present a primary obstacle in quantum computing and sensing applications. In atomic systems, clock transitions (CTs), formed from avoided crossings in an applied Zeeman field, can substantially increase coherence times. We show how CTs can dampen intrinsic and extrinsic sources of quantum noise in molecules. Conical intersections between two periodic potentials form CTs in electron paramagnetic resonance experiments of the spin-polarized singlet fission photoproduct. We report on a pair of CTs for a two-chromophore molecule in terms of the Zeeman field strength, molecular orientation relative to the field, and molecular geometry.

Explore related subjects

physics.chem-phquant-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sina G. Lewis, Kori E. Smyser, Joel D. Eaves. 2021-08-30. Clock Transitions Guard Against Spin Decoherence in Singlet Fission. https://doi.org/10.1063/5.0069344

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

From Heuristics to Machine Learning: The Performance Ceiling for Single-Ion Magnets and Its Electronic Origin

Machine learning (ML) is expected to speed up the discovery of single-ion magnets (SIMs), but does the structural information available before synthesis allow such predictions? For 1215 lanthanide complexes from the SIMDAVIS 1.2.1 database we compared three increasing levels of structural description: tabular features of the coordination site, continuous symmetry measures of the coordination polyhedron, and the complete 3D arrangement of atoms. All three converge to an accuracy near 76%, only slightly above the 71% of the single rule "predict SIM for Dy3+". To explain the failures, we combined multireference ab initio calculations with an inspection of the structures behind the high-confidence errors. The SIMs missed by the geometric models are field-induced relaxers whose ground Kramers doublets are prone to tunnelling, a property invisible to geometric descriptors. Many false positives contain several lanthanide centers or radicals, so their relaxation is collective and outside the single-ion picture. The electronic-structure and connectivity information needed to identify SIMs is therefore not accessible to geometric methods alone. Geometric models remain useful: restricting the screening to compounds with high prediction confidence raises the accuracy to 88% while retaining 48% of the dataset. Building on the analysis of the failures, we propose a strategy that combines simple filters for nuclearity and for radicals with ligand-field descriptors from ab initio calculations.

physics.chem-ph↗
arXiv2026

Absence of demixing in 2D binary mixtures of alcohols

Binary mixtures of two-dimensional, site-based models of alcohols are investigated by computer simulations, focusing on ideal mixing, local clustering and miscibility trends. Four systems are considered: methanol-ethanol, butanol-pentanol, methanol-pentanol, and methanol-octanol, the first two being expected to be ideal mixtures because of the proximity of the molecules, while the last two are examples of mixing distant alcohols. The models retain chemical specificity of their 3D counterparts, thus allowing one to investigate dimensional constraints and non-trivial micro-structurations. It is found that mixtures of short and long alcohols remain miscible, in contrast with the corresponding macroscopic phase separation observed in three dimensions. This issue is analyzed through snapshots, site-site distribution functions, structure factors and Kirkwood-Buff integrals (KBI). It is found that the short range part features are dominated by charge ordering of the hydroxyl head groups, while the long range part develops persistent oscillatory features affecting the determination of the KBI, and suggesting the presence of anomalous domain-like concentration fluctuations. All these findings suggest a complex interplay between charge ordering of the hydrophilic head groups and the hydrophobic tail groups.

physics.chem-ph↗
arXiv2026

A quantum chemistry dataset containing S0-S1 conical-intersection structures of 259k molecules

Conical intersections are key to photoinduced reactions, but comprehensive datasets of their structures remain rare. To address this gap, we built the QCDGE-CI dataset, which contains ground-state and minimum-energy conical-intersection structures for more than 259k small molecules with up to ten heavy atoms (C, N, O, or F). The minimum-energy conical-intersection geometries were computed using the semi-empirical OM2/MRCI method and evaluated through systematic benchmarks with an enlarged active space and CASSCF calculations. These benchmarks support the reliability of the geometries. Cheminformatics analyses further reveal the broad chemical diversity covered by the dataset. The dataset is designed to support machine-learning and data-driven studies of excited-state chemistry, including nonadiabatic processes.

physics.chem-ph↗