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Item type:Publication, Seeking a Quantum Advantage with Trapped-Ion Quantum Simulations of Condensed-Phase Chemical Dynamics(Cornell University, 2023-05-04)Simulating the quantum dynamics of molecules in the condensed phase represents a longstanding challenge in chemistry. Trapped-ion quantum systems may serve as a platform for the analog-quantum simulation of chemical dynamics that is beyond the reach of current classical-digital simulation. To identify a 'quantum advantage' for these simulations, performance analysis of both analog-quantum simulation on noisy hardware and classical-digital algorithms is needed. In this Review, we make a comparison between a noisy analog trapped-ion simulator and a few choice classical-digital methods on simulating the dynamics of a model molecular Hamiltonian with linear vibronic coupling. We describe several simple Hamiltonians that are commonly used to model molecular systems, which can be simulated with existing or emerging trapped-ion hardware. These Hamiltonians may serve as stepping stones toward the use of trapped-ion simulators for systems beyond the reach of classical-digital methods. Finally, we identify dynamical regimes where classical-digital simulations seem to have the weakest performance compared to analog-quantum simulations. These regimes may provide the lowest hanging fruit to exploit potential quantum advantages. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, The Role of Substrates in 2D Spin-Crossover Systems: Insights From Monte Carlo Simulations Within the Ising-Like Model(Wiley, 2025-11-27)Spin-crossover (SCO) molecular solids are a class of coordination compounds exhibiting hysteretic thermal transitions between low-spin (LS) and high-spin (HS) states, making them capable of collective switching between these two states in response to external stimuli such as temperature, pressure, and electric fields. This bistable behavior directly paves the way for breakthrough technological applications in the field of molecular sensors, molecular switches, and actuators. For thermally induced spin transitions, the transition temperature ( T up ) on heating, at which the system switches from the LS to the HS, is strongly influenced by the ligands coordinating the metal center. In this study, we investigate the effect of the substrate on T up in SCO nanostructures, focusing on how subtle substrate-induced interactions can modulate the transition temperature. To this end, we model substrate effects through an extended Ising-like Hamiltonian, solved using Monte Carlo simulations. The results show that substrate interactions can be used to significantly fine-tune the thermal transition temperature, modify the width of the hysteresis, and induce either abrupt or gradual switching as needed. This groundbreaking control offers a radical new perspective for the design and optimization of next-generation SCO devices, enabling the creation, among other applications, of precision-engineered temperature sensors for complex systems.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Exploring the Effects of Extraction Procedures on the Molecular Relaxation Processes of Ulvan Obtained from Ulva Papenfussii(Springer Science+Business Media, 2025-12-01)Ulvan, a biodegradable sulfated polysaccharide from Ulva papenfussii, was obtained using hot water (neutral pH) and alkaline (pH 13) methods to evaluate how extraction conditions modulate its molecular dynamics and dielectric behavior. While compositional changes due to extraction pH are well documented, their impact on the relaxation processes and segmental mobility of ulvan remains largely unexplored. Here, we provide a comprehensive characterization of dielectric permittivity and dielectric loss over a wide frequency (10⁻²-10⁶ Hz) and temperature range (-150 °C to 150 °C), supported by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The alkaline-extracted ulvan showed a lower glass transition temperature (31.6 °C vs. 47.9 °C), higher molecular mobility, and enhanced dielectric response. In contrast, the hot water-extracted sample exhibited greater thermal stability and a more defined dipolar relaxation processes, including a β-relaxation characterized using the Havriliak–Negami model. These findings suggest that hot water-extracted ulvan is more suitable for applications like biodegradable packaging or biomedical films, while alkaline-extracted ulvan is better suited for electroactive materials such as polymer electrolytes. This study highlights the role of extraction strategy in designing ulvan-based sustainable materials. The results underscore the relevance of broadband dielectric spectroscopy as a powerful tool for guiding the design of polysaccharide-based functional materials.3 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Effects of morphology and extraction procedures on the chemical, thermal and dielectric properties of ulvan polysaccharides(Elsevier BV, 2025-09-01)This study presents the first comparative analysis of ulvan polysaccharides extracted from two morphologically distinct Ulva species native to the Peruvian coast: Ulvan papenfussii (blade-like) and Ulvan nematoidea (filamentous). Ulvans were extracted under two different conditions (pH 7 and pH 13) to investigate the combined influence of species-specific morphology and extraction methods on their physicochemical and molecular properties. Regardless of species or extraction conditions, all ulvan samples exhibited complex, multimodal molecular weight distributions, most notably in U. nematoidea. Extraction at pH 7 produced ulvans with higher sulfate contents, with U. nematoidea displaying the highest levels. Structural and chemical characterization via FTIR revealed distinct differences in sulfate positioning and uronic acid content between the species. Thermal analysis (DSC) indicated higher glass transition temperatures in U. nematoidea, likely due to its elevated sulfate content. Dielectric relaxation spectroscopy demonstrated that both taxonomic origin and extraction conditions significantly influence ulvan molecular dynamics. These findings, interpreted through Havriliak-Negami and Vogel-Fulcher-Tammann-Hesse modeling, underscore the importance of algal morphology and processing conditions in shaping the structure-property relationships of ulvans. The results offer new insights into tailoring ulvans for applications as functional bio-based polymers.2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Chitosan Eco-Friendly Approach to Oil Spill Cleanup: A Combined 2D TD-NMR Relaxation and Computational Modeling Study(Springer Science+Business Media, 2026-01-01)This work investigates the molecular interaction between chitosan, an effective and eco-friendly biopolymer, and crude oil components within petroleum emulsions. This mechanistic investigation combines 2D TD-NMR relaxation and computational modeling to understand chitosan’s role as an adsorbent and demulsifier for applications in environmental remediation. We applied a medium molecular mass chitosan to a series of six petroleum emulsions, spanning a representative range of medium and heavy crude oils (viscosities from 32.52 to 182.07 mm2.s-1 at 20 °C). The 2D D-T2 correlation maps were generated using the PFG-CPMG (Pulsed Field Gradient-Carr-Purcell-Meiboom-Gill) sequence to resolve the changes in oil and water mobility following chitosan addition. The key result is the observation of a characteristic shift in the diffusion coefficient (D) and transverse relaxation time (T2) of the oil component upon chitosan introduction. This shift provides direct evidence of the molecular interaction and the disruption of the emulsion stabilizing film. Furthermore, molecular modeling confirms strong water binding, complementing the TD-NMR findings. Overall, the study successfully demonstrates the utility of TD-NMR and molecular dynamics for mechanistic assessment, providing crucial, direct insight into the demulsification role of chitosan within petroleum emulsions.