Showing papers in "Annual Review of Physical Chemistry in 2021"
TL;DR: The method presented has a computational cost and scaling similar to MCSCF, but a quantitative accuracy, even with the present first approximations to the new types of density functionals, that is comparable to much more expensive multireference perturbation theory methods.
Abstract: We present a new theoretical framework, called Multiconfiguration Pair-Density Functional Theory (MC-PDFT), which combines multiconfigurational wave functions with a generalization of density functional theory (DFT). A multiconfigurational self-consistent-field (MCSCF) wave function with correct spin and space symmetry is used to compute the total electronic density, its gradient, the on-top pair density, and the kinetic and Coulomb contributions to the total electronic energy. We then use a functional of the total density, its gradient, and the on-top pair density to calculate the remaining part of the energy, which we call the on-top-density-functional energy in contrast to the exchange-correlation energy of Kohn–Sham DFT. Because the on-top pair density is an element of the two-particle density matrix, this goes beyond the Hohenberg–Kohn theorem that refers only to the one-particle density. To illustrate the theory, we obtain first approximations to the required new type of density functionals by trans...
241 citations
TL;DR: In this article, a review article focuses on the understanding of intersystem crossing (ISC) in molecules, which is a phenomenon of intercombination transitions between states of different electron spin multiplicities but are not familiar with relativistic quantum chemistry.
Abstract: This review article focuses on the understanding of intersystem crossing (ISC) in molecules. It addresses readers who are interested in the phenomenon of intercombination transitions between states of different electron spin multiplicities but are not familiar with relativistic quantum chemistry. Among the spin-dependent interaction terms that enable a crossover between states of different electron spin multiplicities, spin-orbit coupling (SOC) is by far the most important. If SOC is small or vanishes by symmetry, ISC can proceed by electronic spin-spin coupling (SSC) or hyperfine interaction (HFI). Although this review discusses SSC- and HFI-based ISC, the emphasis is on SOC-based ISC. In addition to laying the theoretical foundations for the understanding of ISC, the review elaborates on the qualitative rules for estimating transition probabilities. Research on the mechanisms of ISC has experienced a major revival in recent years owing to its importance in organic light-emitting diodes (OLEDs). Exemplified by challenging case studies, chemical substitution and solvent environment effects are discussed with the aim of helping the reader to understand and thereby get a handle on the factors that steer the efficiency of ISC.
72 citations
TL;DR: A critical summary of approaches developed for quantitative mass spectrometry imaging of metabolites, lipids, and proteins in biological tissues and discuss their current and future applications can be found in this article.
Abstract: Mass spectrometry imaging (MSI) is a powerful, label-free technique that provides detailed maps of hundreds of molecules in complex samples with high sensitivity and subcellular spatial resolution. Accurate quantification in MSI relies on a detailed understanding of matrix effects associated with the ionization process along with evaluation of the extraction efficiency and mass-dependent ion losses occurring in the analysis step. We present a critical summary of approaches developed for quantitative MSI of metabolites, lipids, and proteins in biological tissues and discuss their current and future applications.
51 citations
TL;DR: The second generation of the ALMO-EDA-II is described in this article, where the effects of different physical contributions on changes in observables such as structure and vibrational frequencies upon complex formation are characterized via the adiabatic EDA.
Abstract: Quantum chemistry in the form of density functional theory (DFT) calculations is a powerful numerical experiment for predicting intermolecular interaction energies. However, no chemical insight is gained in this way beyond predictions of observables. Energy decomposition analysis (EDA) can quantitatively bridge this gap by providing values for the chemical drivers of the interactions, such as permanent electrostatics, Pauli repulsion, dispersion, and charge transfer. These energetic contributions are identified by performing DFT calculations with constraints that disable components of the interaction. This review describes the second-generation version of the absolutely localized molecular orbital EDA (ALMO-EDA-II). The effects of different physical contributions on changes in observables such as structure and vibrational frequencies upon complex formation are characterized via the adiabatic EDA. Example applications include red- versus blue-shifting hydrogen bonds; the bonding and frequency shifts of CO, N2, and BF bound to a [Ru(II)(NH3)5]2 + moiety; and the nature of the strongly bound complexes between pyridine and the benzene and naphthalene radical cations. Additionally, the use of ALMO-EDA-II to benchmark and guide the development of advanced force fields for molecular simulation is illustrated with the recent, very promising, MB-UCB potential.
43 citations
TL;DR: In this paper, the authors explore the recent advances in the description and understanding of electrode-electrolyte interfaces with classical molecular simulations, with a focus on planar interfaces and solvent-based liquids, from pure solvent to water-in-salt electrolytes.
Abstract: Many key industrial processes, from electricity production, conversion, and storage to electrocatalysis or electrochemistry in general, rely on physical mechanisms occurring at the interface between a metallic electrode and an electrolyte solution, summarized by the concept of an electric double layer, with the accumulation/depletion of electrons on the metal side and of ions on the liquid side. While electrostatic interactions play an essential role in the structure, thermodynamics, dynamics, and reactivity of electrode-electrolyte interfaces, these properties also crucially depend on the nature of the ions and solvent, as well as that of the metal itself. Such interfaces pose many challenges for modeling because they are a place where quantum chemistry meets statistical physics. In the present review, we explore the recent advances in the description and understanding of electrode-electrolyte interfaces with classical molecular simulations, with a focus on planar interfaces and solvent-based liquids, from pure solvent to water-in-salt electrolytes.
41 citations
TL;DR: In this article, the emerging method of super-resolved cryogenic correlative light and electron microscopy (srCryoCLEM) was reviewed and compared with super-resolution fluorescence microscopy and cryogenic electron tomography (CE...
Abstract: We review the emerging method of super-resolved cryogenic correlative light and electron microscopy (srCryoCLEM). Super-resolution (SR) fluorescence microscopy and cryogenic electron tomography (CE...
34 citations
TL;DR: A range of first-principles quantum mechanics techniques has offered insights, from ground-state density functional theory (DFT) to excited-state theories such as multireference correlated wavefunction methods, in the context of accurately capturing plasmonic effects, with accompanying examples.
Abstract: The size- and shape-controlled enhanced optical response of metal nanoparticles (NPs) is referred to as a localized surface plasmon resonance (LSPR). LSPRs result in amplified surface and interpart...
34 citations
TL;DR: This review summarizes recent progress in the excited-state dynamics of atomically precise gold (Au) nanoclusters (NCs) and provides the perspective on future directions in this area.
Abstract: Understanding the excited-state dynamics of nanomaterials is essential to their applications in photoenergy storage and conversion. This review summarizes recent progress in the excited-state dynam...
31 citations
TL;DR: The evidence for and the consequences of the hypothesis that the plasma membrane is poised near an equilibrium miscibility critical point are focused on.
Abstract: Lateral organization in the plane of the plasma membrane is an important driver of biological processes. The past dozen years have seen increasing experimental support for the notion that lipid org...
29 citations
TL;DR: In this paper, the subtle interplay of site-to-site electronic couplings, exciton delocalization, nonadiabatic effects, and vibronic couplings is investigated.
Abstract: Due to the subtle interplay of site-to-site electronic couplings, exciton delocalization, nonadiabatic effects, and vibronic couplings, quantum dynamical studies are needed to elucidate the details...
24 citations
TL;DR: Structural models show that both the C- and N-terminal extensions are important for controlling oligomerization through domain swapping, and α-Crystallin is particularly amenable to structure determination by solid-state NMR and solution NMR, as well as cryo-electron microscopy.
Abstract: α-Crystallins are small heat-shock proteins that act as holdase chaperones. In humans, αA-crystallin is expressed only in the eye lens, while αB-crystallin is found in many tissues. α-Crystallins have a central domain flanked by flexible extensions and form dynamic, heterogeneous oligomers. Structural models show that both the C- and N-terminal extensions are important for controlling oligomerization through domain swapping. α-Crystallin prevents aggregation of damaged β- and γ-crystallins by binding to the client protein using a variety of binding modes. α-Crystallin chaperone activity can be compromised by mutation or posttranslational modifications, leading to protein aggregation and cataract. Because of their high solubility and their ability to form large, functional oligomers, α-crystallins are particularly amenable to structure determination by solid-state nuclear magnetic resonance (NMR) and solution NMR, as well as cryo-electron microscopy.
TL;DR: In this paper, a multiscale models combining quantum mechanical and classical descriptions are used to simulate properties and processes of complex systems, which is a very popular strategy for modeling complex systems.
Abstract: Multiscale models combining quantum mechanical and classical descriptions are a very popular strategy to simulate properties and processes of complex systems Many alternative formulations have bee
TL;DR: In this paper, two approaches that consider both the explicit atomistic environment and the vibronic transitions are presented. But they do not consider the effects of the chromophore and the environment on equal footing.
Abstract: Including both environmental and vibronic effects is important for accurate simulation of optical spectra, but combining these effects remains computationally challenging. We outline two approaches that consider both the explicit atomistic environment and the vibronic transitions. Both phenomena are responsible for spectral shapes in linear spectroscopy and the electronic evolution measured in nonlinear spectroscopy. The first approach utilizes snapshots of chromophore-environment configurations for which chromophore normal modes are determined. We outline various approximations for this static approach that assumes harmonic potentials and ignores dynamic system-environment coupling. The second approach obtains excitation energies for a series of time-correlated snapshots. This dynamic approach relies on the accurate truncation of the cumulant expansion but treats the dynamics of the chromophore and the environment on equal footing. Both approaches show significant potential for making strides toward more accurate optical spectroscopy simulations of complex condensed phase systems.
TL;DR: In this paper, the authors describe the principles behind the optical modulation of chemical reactivity and selectivity on plasmonic metal nanostructures, and they focus on a less discussed aspect: the induction of new reaction pathways by light excitation.
Abstract: Because plasmonic metal nanostructures combine strong light absorption with catalytically active surfaces, they have become platforms for the light-assisted catalysis of chemical reactions. The enhancement of reaction rates by plasmonic excitation has been extensively discussed. This review focuses on a less discussed aspect: the induction of new reaction pathways by light excitation. Through commentary on seminal reports, we describe the principles behind the optical modulation of chemical reactivity and selectivity on plasmonic metal nanostructures. Central to these phenomena are excited charge carriers generated by plasmonic excitation, which modify the energy landscape available to surface reactive species and unlock pathways not conventionally available in thermal catalysis. Photogenerated carriers can trigger bond dissociation or desorption in an adsorbate-selective manner, drive charge transfer and multielectron redox reactions, and generate radical intermediates. Through one or more of these mechanisms, a specific pathway becomes favored under light. By improved control over these mechanisms, light-assisted catalysis can be transformational for chemical synthesis and energy conversion.
TL;DR: In this article, the authors discuss the development of surface-enhanced Raman spectroscopy (SERS) technology, focusing on its applications in different electrocatalytic reactions (such as oxygen reduction reactions) and at different nanostructure surfaces.
Abstract: As energy demands increase, electrocatalysis serves as a vital tool in energy conversion. Elucidating electrocatalytic mechanisms using in situ spectroscopic characterization techniques can provide experimental guidance for preparing high-efficiency electrocatalysts. Surface-enhanced Raman spectroscopy (SERS) can provide rich spectral information for ultratrace surface species and is extremely well suited to studying their activity. To improve the material and morphological universalities, researchers have employed different kinds of nanostructures that have played important roles in the development of SERS technologies. Different strategies, such as so-called borrowing enhancement from shell-isolated modes and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS)-satellite structures, have been proposed to obtain highly effective Raman enhancement, and these methods make it possible to apply SERS to various electrocatalytic systems. Here, we discuss the development of SERS technology, focusing on its applications in different electrocatalytic reactions (such as oxygen reduction reactions) and at different nanostructure surfaces, and give a brief outlook on its development.
TL;DR: Cascade reactions from enzymes or hybrid bioorganic catalyst systems exhibit extended substrate range, reaction depth, and increased overall performance as mentioned in this paper, and they also have potential in artificial applications due to the possibility of using the target substrate in biofuel cells, electrosynthesis, and biosensors.
Abstract: Enzyme cascades are plentiful in nature, but they also have potential in artificial applications due to the possibility of using the target substrate in biofuel cells, electrosynthesis, and biosensors. Cascade reactions from enzymes or hybrid bioorganic catalyst systems exhibit extended substrate range, reaction depth, and increased overall performance. This review addresses the strategies of cascade biocatalysis and bioelectrocatalysis for (a) CO2 fixation, (b) high value-added product formation, (c) sustainable energy sources via deep oxidation, and (d) cascaded electrochemical enzymatic biosensors. These recent updates in the field provide fundamental concepts, designs of artificial electrocatalytic oxidation-reduction pathways (using a flexible setup involving organic catalysts and engineered enzymes), and advances in hybrid cascaded sensors for sensitive analyte detection.
TL;DR: In this paper, the authors discuss the applications of different physical principles at the microscale and corresponding microfluidic approaches for the measurement of droplet phase state, viscosity, and IFT.
Abstract: Measurements of droplet phase and interfacial tension (IFT) are important in the fields of atmospheric aerosols and emulsion science. Bulk macroscale property measurements with similar constituents cannot capture the effect of microscopic length scales and highly curved surfaces on the transport characteristics and heterogeneous chemistry typical in these applications. Instead, microscale droplet measurements ensure properties are measured at the relevant length scale. With recent advances in microfluidics, customized multiphase fluid flows can be created in channels for the manipulation and observation of microscale droplets in an enclosed setting without the need for large and expensive control systems. In this review, we discuss the applications of different physical principles at the microscale and corresponding microfluidic approaches for the measurement of droplet phase state, viscosity, and IFT.
TL;DR: In this article, a review of nonadiabatic molecular dynamics (NAMD) methods for modeling spin-crossover transitions is presented, with the main focus on spin-orbit couplings.
Abstract: In this article, we review nonadiabatic molecular dynamics (NAMD) methods for modeling spin-crossover transitions First, we discuss different representations of electronic states employed in the grid-based and direct NAMD simulations The nature of interstate couplings in different representations is highlighted, with the main focus on nonadiabatic and spin-orbit couplings Second, we describe three NAMD methods that have been used to simulate spin-crossover dynamics, including trajectory surface hopping, ab initio multiple spawning, and multiconfiguration time-dependent Hartree Some aspects of employing different electronic structure methods to obtain information about potential energy surfaces and interstate couplings for NAMD simulations are also discussed Third, representative applications of NAMD to spin crossovers in molecular systems of different sizes and complexities are highlighted Finally, we pose several fundamental questions related to spin-dependent processes These questions should be possible to address with future methodological developments in NAMD
TL;DR: In this paper, the intrinsic relationships between the structure, properties, and performance of the electrochemical interface is revealed. But, the relationship between the two types of interfaces is not discussed.
Abstract: Revealing the intrinsic relationships between the structure, properties, and performance of the electrochemical interface is a long-term goal in the electrochemistry and surface science communities...
TL;DR: When an intense 1,064-nm continuous-wave laser is tightly focused at solution surfaces, it exerts an optical force on molecules, polymers, and nanoparticles as discussed by the authors.
Abstract: When an intense 1,064-nm continuous-wave laser is tightly focused at solution surfaces, it exerts an optical force on molecules, polymers, and nanoparticles (NPs) Initially, molecules and NPs are
TL;DR: In this paper, the impact of aerosols on the climate, atmosphere, and human health has been investigated, and challenges remain in understanding the effect of aerosol pollution on the environment, climate, and humans.
Abstract: Atmospheric aerosols are suspended particulate matter of varying composition, size, and mixing state. Challenges remain in understanding the impact of aerosols on the climate, atmosphere, and human...
TL;DR: A range of magnetic field-based methods have been introduced to state-selectively manipulate paramagnetic atoms in this article, including external magnetic fields to deflect the atoms and external magnetic sensors.
Abstract: Since external magnetic fields were first employed to deflect paramagnetic atoms in 1921, a range of magnetic field–based methods have been introduced to state-selectively manipulate paramagnetic s...
TL;DR: The ease with which the pH is routinely determined for aqueous solutions masks the fact that the cationic product of Arrhenius acid dissolution, the hydrated proton, or H+(aq), is a remarkably comp...
Abstract: The ease with which the pH is routinely determined for aqueous solutions masks the fact that the cationic product of Arrhenius acid dissolution, the hydrated proton, or H+(aq), is a remarkably comp...
TL;DR: Ionizing rays cause damage to genomes, proteins, and signaling pathways that normally regulate cell activity, with harmful consequences such as accelerated aging, tumors, and cancers but also with....
Abstract: Ionizing rays cause damage to genomes, proteins, and signaling pathways that normally regulate cell activity, with harmful consequences such as accelerated aging, tumors, and cancers but also with ...
TL;DR: In this paper, the authors discuss the recent developments and applications of vibrational sum-frequency generation (VSFG) microscopy, which can resolve systems without inverting the system.
Abstract: In this review, we discuss the recent developments and applications of vibrational sum-frequency generation (VSFG) microscopy. This hyperspectral imaging technique can resolve systems without inver...
TL;DR: In this paper, a review summarizes the mechanisms behind aerosol dry deposition, including measurement approaches, field observations, and modeling studies, and identifies several gaps in the literature, including deposition over the cryosphere (i.e., snow and ice surfaces) and the ocean; in addition, new techniques to measure black carbon fluxes.
Abstract: Aerosols are liquid or solid particles suspended in the atmosphere, typically with diameters on the order of nanometers to microns. These particles impact air quality and the radiative balance of the planet. Dry deposition is a key process for the removal of aerosols from the atmosphere and plays an important role in controlling the lifetime of atmospheric aerosols. Dry deposition is driven by turbulence and shows a strong dependence on particle size. This review summarizes the mechanisms behind aerosol dry deposition, including measurement approaches, field observations, and modeling studies. We identify several gaps in the literature, including deposition over the cryosphere (i.e., snow and ice surfaces) and the ocean; in addition, we highlight new techniques to measure black carbon fluxes. While recent advances in aerosol instrumentation have enhanced our understanding of aerosol sources and chemistry, dry deposition and other loss processes remain poorly investigated.