Floquet spin states in OLEDs.

Electron and hole spins in organic light-emitting diodes constitute prototypical two-level systems for the exploration of the ultrastrong-drive regime of light-matter interactions. Floquet solutions to the time-dependent Hamiltonian of pairs of electron and hole spins reveal that, under non-perturbative resonant drive, when spin-Rabi frequencies become comparable to the Larmor frequencies, hybrid light-matter states emerge that enable dipole-forbidden multi-quantum transitions at integer and fractional g-factors. To probe these phenomena experimentally, we develop an electrically detected magnetic-resonance experiment supporting oscillating driving fields comparable in amplitude to the static field defining the Zeeman splitting; and an organic semiconductor characterized by minimal local hyperfine fields allowing the non-perturbative light-matter interactions to be resolved. The experimental confirmation of the predicted Floquet states under strong-drive conditions demonstrates the presence of hybrid light-matter spin excitations at room temperature. These dressed states are insensitive to power broadening, display Bloch-Siegert-like shifts, and are suggestive of long spin coherence times, implying potential applicability for quantum sensing.

The free-energy barrier to hydride transfer across a dipalladium complex.

We use density-functional theory molecular dynamics (DFT-MD) simulations to determine the hydride transfer coordinate between palladium centres of the crystallographically observed terminal hydride locations, Pd-Pd-H, originally postulated for the solution dynamics of the complex bis-NHC dipalladium hydride [{(MesIm)2CH2}2Pd2H][PF6], and then calculate the free-energy along this coordinate. We estimate the transfer barrier-height to be about 20 kcal mol(-1) with a hydride transfer rate in the order of seconds at room temperature. We validate our DFT-MD modelling using inelastic neutron scattering which reveals anharmonicity of the hydride environment that is so pronounced that there is complete failure of the harmonic model for the hydride ligand. The simulations are extended to high temperature to bring the H-transfer to a rate that is accessible to the simulation technique.

Panic disorder. An overlapping or independent entity?

We compared three groups of patients with panic disorder, generalised anxiety disorder and major depressive episode with a control group. Methods of comparison included a clinical profile of the patients, assessed by the Arabic version of the Present State Examination (PSE), a psychological battery of tests measuring personality traits and depressive and anxiety states, and the dexamethasone suppression test (DST) as a biological marker. Our data showed that psychological assessment and DST did not significantly differentiate between the three disorders. Despite a symptom overlap between the disorders, however, some symptoms were associated significantly more often with one disorder than another. Patients with panic disorder differed from patients with major depressive episode in showing more situational, avoidance and free floating anxiety, and more anxious foreboding. They showed less self-negligence, ideas of guilt, early awakening and social withdrawal. Compared with patients with generalised anxiety disorder, patients with panic disorder showed more loss of interest and muscle tension and less anxious foreboding, restlessness, inefficient thinking, social withdrawal and delayed sleep. Our conclusion is that the clinical course and the symptom profile of panic disorder justifies its existence as an independent diagnostic category.