Controlling electron transfer and related chemical processes through polaritons has emerged as a promising direction in chemical physics. We present a general framework for electron transfer in molecules strongly coupled to polaritons. The theory is formulated within macroscopic quantum electrodynamics, a quantization scheme for electromagnetic fields in non-homogeneous, dispersive, and lossy media. To capture both molecular and dielectric contributions, our formulation incorporates two baths: molecular vibrations and a dielectric-photonic continuum that generates polaritons. This formulation is then transformed into a numerically tractable form that can be naturally combined with methods such as the pseudomode approach or the hierarchical equations of motion. Using a molecule above a plasmonic surface as an example, we show that the framework captures accurate dynamics across light-matter coupling regimes, thereby providing a powerful tool for investigating polariton-mediated electron transfer.

We develop a microscopic diagrammatic theory for cavity-mediated photon scattering in a topological one-dimensional insulator described by the Su-Schrieffer-Heeger model. Within the velocity-gauge formulation, we derive the photon self-energy and vertex corrections arising from virtual electron-hole excitations coupled to a quantized cavity mode, and we evaluate the resulting polariton dispersion and two-photon correlation spectra. Our analysis shows that vacuum fluctuations of the cavity field induce a momentum-resolved self-energy that mixes conduction and valence bands through virtual photon exchange, producing interband hybridization and avoided crossings in the electronic dispersion. This "cavity dressing" is symmetry-dependent, vanishing at the Brillouin-zone edge where the dipole matrix element is zero, and its strength is controlled by the spatial coherence range ζ≈(lc/a)2 of virtual excitations. We further examine how the cavity modifies nonlinear optical observables, including the Kerr nonlinearity and biphoton spectral entanglement, and identify the regimes where these effects become sensitive to the underlying topological phase. The theoretical framework established here provides a unified description of light-matter coupling in topological and polaritonic systems, bridging solid-state cavity QED with the emerging field of cavity-modified quantum materials. Our results suggest that engineered photonic environments can coherently reshape the electronic landscape of topological insulators, offering new routes to control collective electronic and optical phenomena through vacuum-field fluctuations.

We investigate two nitrogen-containing isomers of polycyclic aromatic hydrocarbons, quinoline and isoquinoline, of composition C9H7N in collisions with 7 keV O+ and 48 keV O6+ projectile ions. By employing ion-ion coincidence mass spectrometry, we determine branching ratios for H-loss, C2H2-loss, and HCN-loss dissociation channels of Q2+ and IQ2+. The overall contribution of HCN loss is found to be the dominant decay channel. A comparison with the results of a parallel experiment on naphthalene, the simplest PAH, reveals that HCN loss in both isomers has a higher propensity than the analogous C2H2 loss of naphthalene. The positional identity of the nitrogen atom in the two isomers mainly manifests in many-body fragmentation of their dications. Potential energy surfaces of Q2+ and IQ2+ are further computed to explore complete fragmentation mechanisms. Parent dications (Q2+ and IQ2+) are identified to isomerize via seven-membered ring structures before elimination of C2H2 and HCN. While prompt dissociation is the primary pathway, the dominant channel of each neutral-loss class also exhibits delayed fragmentation.

An efficient chirp pulse-based mixing technique, Adiabatic Linearly FREquency Swept reCOupling (AL FRESCO), is introduced for establishing broadband two-dimensional (2D) 13C-13C dipolar correlations in uniformly 13C-labeled protein samples. AL FRESCO utilizes a single or a series of frequency-swept (chirped) pulses applied to homonuclear spin pairs (e.g., 13Cs, 15Ns, or 1Hs) to mediate homonuclear correlations under magic-angle spinning (MAS). Originally developed for ultrafast MAS, we demonstrate that AL FRESCO performs robustly across a wide range of MAS rates. The AL FRESCO method exhibits strong immunity to dipolar truncation, allowing efficient recoupling of long-range interactions even in the presence of dominant short-range dipolar couplings and regardless of the chemical shift difference between the recoupled sites. A distinctive feature of AL FRESCO is its use of weak radiofrequency (rf) fields (5-20 kHz), independent of the MAS rate, significantly reducing sample heating and enabling extended mixing times (>1 s). This facilitates the observation of long-range correlations that are often inaccessible using conventional recoupling techniques under ultrafast MAS rates. The effectiveness of the method is governed by key parameters such as rf amplitude and envelope shape, dwell time (Δt), and sweep bandwidth. Numerical simulations and average Hamiltonian theory offer insight into the recoupling mechanism. Experimental validation was carried out via 2D 13C-13C correlation spectroscopy at fast, moderate, and slow MAS rates using three different protein systems: uniformly 13C,15N-labeled transthyretin, selectively 13C-[T,W]-labeled CrgA, and uniformly 13C,15N-labeled GB1.

Using hybrid solvation model has become an important way to simulate the dynamics of electrochemical solid-liquid interfaces under realistic solvation and potential. However, since it typically relies on fully covering explicit solvent layers, it suffers from high computational cost and the dissolution of solvent molecules into the implicit solvent. To address these challenges, we present a hybrid explicit-droplet/implicit solvation model implemented based on VASPsol++, which enables efficient constant-potential molecular dynamics simulations around local reactive sites. This model employs an algorithm to exclude implicit solvent within the droplet and a velocity-reflection algorithm that prevents explicit solvent molecules from dissolving into the implicit solvent. It features both radius- and density-constant implementations and integrates a continuous cavity. Validated with established water-layer models, the droplet approach reliably replicates key interfacial properties, such as electron-count fluctuations and free-energy barriers from enhanced sampling calculations, in exemplar systems including Co-N-C motifs and MoS2 edges. Notably, this model accelerates barrier-calculation speed by 2-4 times, depending on slab size and specific settings, while providing reliable results. This study offers a new tool through which simulating the electrochemical interface using constant-potential molecular dynamics is significantly accelerated and more broadly accessible.

We simulate the coherence of two coupled electron spins interacting with a bath of nuclei using the generalized cluster correlation expansion method. An exchange interaction between the electrons facilitates a family of entangling gates that can be spoiled by nuclear-induced dephasing. Consequently, we study the dephasing of the coherent two-electron system by characterizing the T2 and T2* of the two-electron reduced density matrix for various system parameters in the range mimicking magnetic molecules, including magnetic field strength and orientation, exchange interaction strength, distance between the two spins, minimum distance between electron and nuclei and between nuclei, and nuclei density. We find the optimal regime for each parameter in which the coherence time is maximized and provide a physical understanding of it.

Aggregation processes in systems of planar macromolecules and colloids drive a broad range of phenomena in natural systems and soft materials. Depending on the chemical architecture, intermolecular interactions in these systems may favor different relative pair orientations, such as stacking face-face or percolating edge-edge arrangements. In this work, we employ a versatile coarse-grained interaction model for disk-like particles to provide a general framework to rationalize the thermotropic formation of aggregates and predict the topology of the resulting suprastructures. Monte Carlo and Brownian dynamics simulations show that, with appropriate tuning of the interactions, discotics spontaneously nucleate into clusters with globular, planar, or stacked geometries, leading to materials with specific internal order and associated physicochemical properties.

We present a geometric representation in phase space of the classical action. Specifically, we find three seemingly unrelated interpretations for the action as the sum of signed areas of shapes in phase space. By using the Poincaré-Cartan integral invariants in extended phase space, we are able to show the equivalence between all three. As a concrete example, we consider the 1D harmonic oscillator, but the results are general for arbitrary potentials and numbers of dimensions.

As a kind of energetic material, explosives would face an environment of high-pressure during initiation to detonation or under shock waves. Under such conditions, explosives would experience a phase transition and even directly decompose. Therefore, there is a need to achieve the high-pressure evolution of explosives. 3,4-dinitropyrazole (DNP), which has excellent energy and sensibility, can be used as a potential carrier of melt cast explosive to replace TNT. However, the structural evolution of DNP with the increase in pressure remains elusive. With the help of diamond anvil cell technology, in situ high-pressure angle-dispersive x-ray diffraction (ADXRD) and Raman spectra were performed to investigate the structural variations of DNP. Both ADXRD and Raman experiments indicated that the DNP experienced a phase transition in the pressure range between 6.1 and 9.2 GPa. After carefully analyzing the Hirshfeld surface, first-principles calculations, and Raman spectra, we suggested that the newly generated N-H⋯N hydrogen bonds should be responsible for these high-pressure changes. The DNP crystal packing patterns have been changed from 1D molecular tapes to 2D hydrogen bonded networks. This research systemically investigated the high-pressure structural changes of DNP and studied the evolution of weak intermolecular interactions, so it built the relationship between phase transition and weak intermolecular interactions.

Nitric oxides are primary contributors to air pollution. Examining their chemical transformations is crucial for developing effective clean air strategies. In this study, we studied the reactions between cationic tantalum clusters Tan+ (n = 1-16) and NO, utilizing our customized laminar flow tube reactor coupled with a tandem quadrupole mass spectrometer. The experimental results indicate that the reaction pathways of Tan+ clusters vary with cluster size: for smaller tantalum clusters Tan+ (n ≤ 5), the reaction products are mainly composed of TanN+ and TanO+, suggesting direct N-O dissociation or bimolecular reaction to release N2O or NO2 mediated by small metal clusters. In contrast, the larger clusters Tan≥6+ exhibit a range of reaction products, facilitated by the favorable adsorption of multiple molecules to generate the Tan(NO)m+ and TanO(NO)m+ series. Theoretical calculations reveal that the energetics and reaction dynamics differ among Tan+ clusters of varying sizes. This study clarifies the substantial size effect of the Tan+ clusters in reactions with nitric oxide and underscores the importance of small Ta clusters for NO elimination and NOx conversion.

Low-energy (0-14 eV) electron-driven processes in a racemic mixture of the chiral abscisic acid (ABA) molecules are studied using dissociative electron attachment (DEA) spectroscopy under gas-phase conditions. DFT calculations are employed to understand the electronic structure of the ABA molecule to assign the experimental findings. The lowest two normally empty π* molecular orbitals of ABA are predicted to lie in a bound region, whereas the vertical electron attachment energy to occupy the π3* LUMO+2 orbital is estimated to be 1.33 eV. The long-lived (90 μs) parent molecular negative ions are formed by thermal electron attachment via vibrational Feshbach resonance. The adiabatic electron affinity of the ABA molecule is experimentally estimated to be about 0.9 eV. With very few exceptions, the fragmentation of ABA by resonance electron attachment occurs at thermal electron energy, the dominant decay being associated with the formation of the 4-oxoisophorone negative ion (m/z = 152) and the isomeric form of the sorbic acid molecule as a neutral counterpart. The structure of ABA microbial metabolites coincides with that of the DEA products with m/z = 152, 204, and 220 and of the neutral species generated as a counterpart of the m/z = 111 negative ions. The likely relation of these findings to electron-triggered biological processes is briefly discussed in the framework of electron donation to ABA from the microbial nanowires.

Metastable states appear as long-lived intermediate states in various natural transport phenomena, which are governed by energy landscapes. As such, these intermediate metastable states dominate the system's dynamics at coarse grained times. Moreover, they can strongly influence the overall pathways through which the energy landscape is explored. Therefore, quantifying these metastabilities is crucial for uncovering the key details of the underlying landscape. Here, we introduce a robust method based on a generalized many-body Arrhenius law to identify metastable states in escape problems involving interacting particles with excluded volume. Experimental platforms such as colloidal transport or macromolecular translocation through biological pores can offer promising settings to validate our predictions.

The fragment-based approach is a promising strategy for applying correlated-wavefunction methods to lattice energies of molecular solids. A key requirement is the efficient inclusion of the long-distance and nonadditive contributions to the many-body expansion (MBE) of the lattice energy. This is especially important in crystals of polar molecules, where MBE converges slowly with distance. In this context, we compare the simplest coupled-cluster approach-the random-phase approximation (RPA)-against the well-established methodology of Møller-Plesset (MP) perturbation theory. Using the examples of solid ammonia, methanol, and formic acid, we show that the RPA with singles corrections based on the Kohn-Sham (KS) Perdew-Burke-Ernzerhof (PBE) orbitals yields near-benchmark accuracy for the two-body contributions. However, for any PBE-based variant of RPA, the three- and four-body contributions suffer from artifacts. For the nonadditive terms, the Hartree-Fock (HF) orbitals appear necessary. In fact, we find that the HF-based RPA with additional corrections recovers the nonadditive interactions about as accurately as the more expensive MP2.5 method. This is a departure from the typical KS-based RPA and an indication that the HF-based RPA can serve as an alternative to the usual MP methods in accurate approximations of the crystal lattice energy.

Understanding and controlling spin relaxation in molecular qubits is essential for developing chemically tunable quantum information platforms. We present a first-principles-parametrized analytical framework for evaluating spin relaxation dynamics in vanadyl phthalocyanine (VOPc) and its oxygenated derivative, VOPc(OH)8. By expanding the spin Hamiltonian in vibrational normal modes and computing both linear and quadratic spin-phonon coupling tensors via finite differences of the g-tensor, we construct a relaxation tensor that enters a Lindblad-type master equation, capturing both direct (one-phonon) and Raman (two-phonon) processes. A mode-resolved analysis reveals that relaxation is funneled through only a handful of low-frequency vibrations: in VOPc, three out-of-plane distortions of the phthalocyanine ring and V-O unit dominate, whereas in VOPc(OH)8, the additional oxygens shift these modes downward and suppress two of them, leaving a single strongly coupled mode as the main decoherence pathway. Both longitudinal (T1) and transverse (T2) relaxation are governed by this same set of vibrational modes, indicating that coherence loss is controlled by a common microscopic mechanism. This mode-selective picture offers a design strategy for engineering longer-lived molecular qubits.

A non-standard analysis of the dielectric loss spectrum of liquid water in the Debye relaxation region (108-1013 Hz) is carried out in terms of dynamic conductivity σ(ν), with the Debye dielectric loss dome represented as the spectral trapezoid of an overdamped Lorentzian oscillator. Debye relaxation, in this framework, reflects the low-frequency tail of a strongly overdamped molecular oscillatory process with a characteristic frequency around 0.3 THz. The effectiveness of the σ-approach for identifying the relationship between the dielectric response and the self-diffusion D and viscosity η coefficients of liquid water is shown. Analytical expressions that link the dielectric and transport parameters of liquid water over a wide temperature range, from the triple point to the critical point (273-647 K), are derived.

Ion doping is one of the most effective strategies to tailor the piezoelectric properties of alkali niobate ceramics. However, its underlying mechanisms remain insufficiently understood. In this work, the structural, ferroelectric, and piezoelectric properties of the selected A- or B-site monodoping and codoping in orthorhombic KNbO3(KN) are studied by density-functional calculations. A-site substitutions include alkali (Li, Na, Rb, Cs), alkaline-earth (Mg, Ca, Sr, Ba), and Bi ions, while B-site doping involves Nb replacement with isovalent (V, Ta, P, As), group IVB (Ti, Zr, Hf), and Bi atoms. Two co-doping combinations, (Na, Sb) and (Ba, Zr), are also studied. The orientational averaged shear, transverse, and longitudinal piezoelectric coefficients d̄15*, d̄31*, and d̄33* of the A/B-site monodoping and codoping in KN piezoceramics are calculated from the results of single crystals. The calculated values clearly indicate that the substitution of Na, Cs, and Ca at the A-site can result in higher piezoelectricity, while the incorporation of V, Ta, Ti, Bi, and Sb to substitute Nb atoms induces better piezoelectric performance. Moreover, the codoping technique of (Na, Sb)- and (Ba, Zr)-doped KN crystals significantly enhances the piezoelectricity compared with the pure KN and those monodoping cases. These findings demonstrate that ion doping plays a critical role in flattening the energy landscape and enhancing the piezoelectric performance of perovskite ferroelectrics.

We investigated fragmentation dynamics of OCS2+ after photoinduced double ionization by combining static potential energy surface (PES) analysis with ab initio molecular dynamics (AIMD) and surface-hopping AIMD (SH-AIMD). In the ground state, AIMD shows that the isomerization pathway from OCS2+ to COS2+, although accessible on the static PES, is dynamically hidden. Trajectories rarely follow it because it requires unrealistically high bending excitation, whereas S+ dissociation proceeds without such a constraint. Consequently, energy released upon ionization is funneled more efficiently into dissociation, favoring S+ dissociation over isomerization. For excited states, SH-AIMD trajectories launched from the lowest triplet 3Π states and the 23Δ state reproduce the observed fragmentation: predominant S+ dissociation with minor O+ formation. The isomerization process leading to the COS2+ structure was not observed in the simulations. These results are consistent with experimental observations. Notably, for the O+ channel, we likely achieve the first AIMD reproduction of the experimental appearance threshold using only triplet states and no external laser fields. This indicates that vibronic coupling via bending motion is essential to enable O+ release, although its probability remains small relative to S+ dissociation. Overall, fragmentation in OCS2+ is governed by the interplay of vibronic coupling and dynamical effects: bending vibrations can facilitate O+ release, whereas isomerization to COS2+ is dynamically suppressed by the requirement of extreme bending excitation. The high density of states in the excited manifold further underscores the strongly nonadiabatic character of OCS2+. Our results connect static PES features with trajectory-based dynamics, offering new insight into selective fragmentation in polyatomic dications.

Being a numerically exact method for the simulation of dynamics in open quantum systems, the hierarchical equations of motion (HEOM) approach still suffers from the curse of dimensionality. In this study, we propose a novel multiconfigurational Ehrenfest (MCE)-HEOM method, which introduces the MCE ansatz to the second quantization formalism of HEOM. Here, the MCE equations of motion are derived from the time-dependent variational principle in a composed Hilbert-Liouville space, and each MCE coherent-state basis can be regarded as having an infinite hierarchical tier such that the truncation tier of auxiliary density operators in MCE-HEOM can also be considered to be infinite. As demonstrated in a series of representative spin-boson models, our MCE-HEOM significantly reduces the number of variational parameters and could efficiently handle the strong non-Markovian effect, which is difficult for conventional HEOM due to the requirement of a very deep truncation tier. MCE-HEOM is further applied to the 7-site Fenna-Matthews-Olson complex to study energy transfer in photosynthesis, and the results indicate that multi-site and multi-bath cases can also be accurately described with high efficiency. Compared to MCE, MCE-HEOM reduces the number of effective bath modes and circumvents the initial sampling for finite temperatures, eventually resulting in a significant reduction in computational cost.

Scattering resonances are quantum phenomena arising from the decay of metastable collision complexes trapped by a centrifugal barrier or supported by a closed channel that is coupled to a scattering state. As such, resonances can provide significant insights into the scattering process and serve as a sensitive probe of the interaction potential. In this article, we present a detailed analysis of a cluster of shape resonances associated with the orbital angular momentum L = 5 in the j = 2 → j' = 0 rotational transition in Ne + D2 collisions for vibrational levels v = 0, 1, and 4. The energies and lifetimes of the resonances arising from different values of the total angular momentum quantum number J were analyzed through numerical fitting of the scattering matrix and employing a one-dimensional model based on an effective potential. We further investigated the sensitivity of the resonances to changes in the alignment of the D2 internuclear axis with respect to the initial relative velocity. Our results show that resonances can be exquisitely controlled by carefully selecting the initial alignment of the D2 molecule. In particular, not only the intensity of the resonance can be modulated but also the shape of the overall resonance profile can be altered, depending on the stereodynamical preferences of the individual resonances that contribute to the cluster.

Conventional density functional theory (DFT) is unable to predict inverted singlet-triplet gaps, largely because the underlying Kohn-Sham framework does not capture correlation effects arising from double excitations. This limitation has hindered the accurate description of systems where singlet-triplet inversion plays a key role, for example, in thermally activated delayed fluorescence emitters. To address this issue, we develop a modified long-range corrected functional, LC-BLYP(D), that augments the ground-state description with MP2 correlation and incorporates CIS(D) correlation for the excited state. By explicitly accounting for correlation effects that are absent in conventional functionals, LC-BLYP(D) provides a more balanced treatment of ground- and excited-state energetics. In addition, we introduce a single-step tuning protocol for the range-separation parameter, designed to optimize the performance of LC-BLYP(D) without the need for iterative procedures. When applied in combination, the tuned LC-BLYP(D) functional reproduces inverted singlet-triplet gaps with a mean absolute error of 0.022 eV, representing a substantial improvement over standard DFT approaches. These results demonstrate that the incorporation of correlated wavefunction-based corrections into a range-separated framework not only overcomes a fundamental shortcoming of DFT but also offers a practical and accurate tool for investigating excited-state properties in complex molecular systems.

We develop a replicated liquid theory for structural glasses that exhibit spatial variation of physical quantities along one axis, say z-axis. The theory becomes exact with an infinite transverse dimension d - 1 → ∞. It provides an exact free-energy functional with a space-dependent glass order parameter Δab(z). As a first application of the scheme, we study diverging lengths associated with dynamic/static glass transitions of hard spheres with/without a confining cavity. The exponents agree with those obtained in previous studies on related mean-field models. Moreover, it predicts a non-trivial spatial profile of the glass order parameter Δab(z) within the cavity, which exhibits a scaling feature approaching the dynamical glass transition.