The Journal of Physical Chemistry Letters最新文献

Traditional catalyst optimization, based on the Sabatier principle, encounters performance limits due to the scaling relationship between binding energies for a series of adsorbates. This restriction prevents independent optimization of the reactant activation and product desorption. Single-atom catalysts (SACs) offer a unique advantage, with their ability to dynamically adjust the metal–support coordination environment. This flexibility allows us to apply hemilability, a concept from homogeneous catalysis, to modulate catalytic activity. Hemilability, which involves the reversible opening and closing of the coordination site, enables SACs to dynamically alter their electronic structure, effectively decoupling the competing requirements of activation and desorption. In this Perspective, we highlight how SACs, with hemilabile metal–support coordination, represent a promising strategy to bypass the limitations imposed by the scaling relationship. We also discuss the experimental challenges and future opportunities for directly observing and controlling these dynamic processes in SACs, thus presenting a powerful way for developing more efficient catalytic systems.

Two-dimensional (2D) metal–semiconductor (MS) junctions with their atomically thin nature are crucial for nanoelectronics. However, van der Waals (vdW) junctions face interfacial tunneling barriers, and lateral junctions suffer from chemical bonding disorders, both limiting carrier transport. Herein, based on the layer-dependent semiconductor-to-semimetal transition in 2D bismuthene (Bi) and antimonene (Sb), lateral seamless MS junctions with native chemical bonds are constructed to inhibit tunneling barriers and produce high-quality interfaces. These coherent junctions exhibit superior transport properties, yielding a significant current response at moderate bias as continuous covalent bonding removes vdW gaps and defects. In optoelectronic applications, the photogenerated carrier lifetimes in Bi and Sb reach 61.62 and 286.16 ns owing to weak electron–phonon coupling. Furthermore, the transport and optoelectronic properties of these MS junctions exhibit superior environmental resistance, while O₂-induced trap states in Sb enhance photoconductive gain. This work provides a theoretical foundation for designing high-performance electronic and optoelectronic devices.

The photophysics of nucleobases has been the subject of both theoretical and experimental studies over the past decades due to the challenges posed by resolving the steps of their radiationless relaxation dynamics, which cannot be described in the framework of the Born–Oppenheimer approximation (BOA). In this context, the ultrafast dynamics of 2-thiouracil has been investigated with a time-resolved NEXAFS study at the Free Electron Laser FLASH. Near Edge X-ray Absorption Fine Structure spectroscopy (NEXAFS) can be used to observe electronic transitions in ultrafast molecular relaxation. We performed time-resolved UV-pump/X-ray probe absorption measurements at the sulfur 2s (L1) and 2p (L2/3) edges. We are able to identify absorption features corresponding to the S2 (ππ*) and S1 (nπ*) electronic states. We observe a delay of 102 ± 11 fs in the population of the nπ* state with respect to the initial optical excitation and interpret the delay as the time scale for the S2 → S1 internal conversion. We furthermore identify oscillations in the absorption signal that match a similar observation in our previous X-ray photoelectron spectroscopy study on the same molecule.

Perovskites have attracted considerable attention in materials science due to their promising applications in photovoltaics and photocatalysis. Accurate prediction of their electronic band gap is essential for optimizing the performance. Traditional computational methods for band gap prediction often face a trade-off between accuracy and computational efficiency. General density functional theory (DFT) calculations typically underestimate band gap values, while the more accurate quasi-particle method demands substantial computational resources. In this study, a multistep machine learning framework was developed for efficient screening of semiconductor double perovskites. Furthermore, we proposed an interpretable descriptor that can predict quasi-particle band gaps of perovskites with a precision of over 90% accuracy. Using this approach, we screened 4,507 perovskite candidates and identified 94 structures that have suitable band gaps and are lead-free. Among these, six candidate structures were selected for further verification based on their photocatalytic potential and thermal stability.

The Bethe–Salpeter equation (BSE) combined with the Green’s function GW method has been successfully transformed into a robust computational tool to describe light–matter interactions and excitation spectra for molecules, solids, and materials from first principles. Due to its ability to accurately describe charge transfer and Rydberg excitations, GW-BSE is already an established and cost-efficient alternative to time-dependent density functional theory. This raises the question whether the GW-BSE approach can become a more general framework for molecular properties beyond excitation energies. In this Mini-Review, we recapitulate recent endeavors along this point in terms of both theoretical and practical developments for quantum chemistry, physical chemistry, and related fields. In doing so, we provide guidelines for current applications to chemical challenges in collaboration with experimentalists as well as to future developments to extended the GW-BSE toolkit.

Accurate vibrational spectra are essential for understanding how molecules behave, yet their computation remains challenging, and benchmark data to reliably compare different methods are sparse. Here, we present high-accuracy eigenstate computations for the six-atom, 12-dimensional acetonitrile molecule, a prototypical, strongly coupled anharmonic system. Using a density matrix renormalization group (DMRG) algorithm with a tree-tensor-network-state (TTNS) ansatz, a refinement using TTNSs as basis set, and reliable procedures to estimate energy errors, we compute up to 5,000 vibrational states with error estimates below 0.0007 cm^–1. Our analysis reveals that previous works underestimated the energy error by up to 2 orders of magnitude. Our data serve as a benchmark for future vibrational spectroscopy methods, and our new method offers a path toward similarly precise computations of large, complex molecular systems.