# Physical chemistry

• Article
| Open Access

### Structure and dynamics of the drug-bound bacterial transporter EmrE in lipid bilayers

The small proton-coupled transporter EmrE confers multidrug resistance in bacteria. The structure of drug-bound EmrE in phospholipid bilayers is now determined using solid-state NMR. The structure provides detailed insights into the molecular mechanism of substrate recognition by this transporter.

• Alexander A. Shcherbakov
• , Grant Hisao
•  & Mei Hong
• Article
| Open Access

### Controlling hot electron flux and catalytic selectivity with nanoscale metal-oxide interfaces

Chemical interaction between metal and oxide supports is an important molecular-level factor that influences the catalytic selectivity of a desirable reaction. Here, using Pt nanowires/TiO2 catalytic nanodiodes, the authors investigate an enhancement of both selectivity and hot electron generation on metal-oxide interfacial sites.

• Si Woo Lee
• , Jong Min Kim
•  & Jeong Young Park
• Article
| Open Access

### The corona of a surface bubble promotes electrochemical reactions

Gas bubbles forming on the surface of an electrode, a phenomenon common to several industrial electrolytic processes, are usually perceived as inert, passivating entities. Here, the authors show that that this general assumption does not hold for gas bubbles masking anodes operating in water.

• Yan B. Vogel
• , Cameron W. Evans
•  & Simone Ciampi
• Article
| Open Access

### Optical-field driven charge-transfer modulations near composite nanostructures

Controlling and modulating charge transfer dynamics in composite nanostructures, though promising for optoelectronic applications, remains a challenge. Here, the authors report optical control of charge separation and recombination processes in organic semiconductor-based composite nanostructures.

• Kwang Jin Lee
• , Elke Beyreuther
•  & Pascal André
• Article
| Open Access

### Differential guest location by host dynamics enhances propylene/propane separation in a metal-organic framework

Porous materials acting as molecular sieves for propylene/propane separation are important for the petrochemical industry. Here the authors show an example of how specific guest-host interactions can result in structural changes in the porous host and shut down diffusion of one of the two similar guest molecules.

• Dmytro Antypov
• , Aleksander Shkurenko
•  & Matthew S. Dyer
• Article
| Open Access

### High pressure synthesis of phosphine from the elements and the discovery of the missing (PH3)2H2 tile

Chemical elements at high pressure may behave more consistently with their periodic properties than they do at ambient conditions. The authors report the synthesis of PH3 from black phosphorous and hydrogen, and the crystallization of the van der Waals compound (PH3)2H2 which fills a gap in the chemistry of adjacent elements in the periodic table.

• Matteo Ceppatelli
• , Demetrio Scelta
•  & Maurizio Peruzzini
• Article
| Open Access

### Two-dimensional electronic spectroscopy of bacteriochlorophyll a with synchronized dual mode-locked lasers

Multidimensional electronic spectroscopy techniques still have many limitations. Here, the authors introduce a 2D electronic spectroscopy technique that uses broadband, synchronized mode-locked lasers to study dynamics on a wide range of timescales.

• JunWoo Kim
• , Jonggu Jeon
•  & Minhaeng Cho
• Article
| Open Access

### The role of mixed vibronic Qy-Qx states in green light absorption of light-harvesting complex II

The green component of the solar spectrum can efficiently drive natural photosynthesis, but the process has been little investigated due to the complexity of the excited states involved. Here the authors utilize polarization-dependent two-dimensional electronic-vibrational spectroscopy to define the origin and dynamics of these states in light-harvesting complex II.

• Eric A. Arsenault
• , Yusuke Yoneda
•  & Graham R. Fleming
• Article
| Open Access

### Vibrational couplings and energy transfer pathways of water’s bending mode

Vibrational energy transfer in water involves intermolecular coupling of O-H stretching modes, but much less is known about the role of the bending modes. Here the authors, combining static and femtosecond infrared, Raman, and hyper-Raman spectroscopy and ab initio molecular dynamics simulations, provide insight into the energy dynamics of the bend vibrations.

• Chun-Chieh Yu
• , Kuo-Yang Chiang
•  & Yuki Nagata
• Article
| Open Access

### Sensing the allosteric force

Almost all allosteric systems are large multi-domain proteins which complicates the investigation of the mechanism in atomistic detail. Here authors designed a small allosteric protein system using the photocontrollable PDZ3 domain, that allows controlling allostery between the binding and allosteric site in both directions.

• Olga Bozovic
• , Brankica Jankovic
•  & Peter Hamm
• Article
| Open Access

### Attosecond spectroscopy reveals alignment dependent core-hole dynamics in the ICl molecule

Here the authors report a study measuring lifetimes of core-hole states of ICl molecule using attosecond transient absorption spectroscopy. They find that lifetimes depend on the alignment of the orbital relative to the molecular axis.

• Hugo J. B. Marroux
• , Ashley P. Fidler
•  & Daniel M. Neumark
• Article
| Open Access

### Liquid water contains the building blocks of diverse ice phases

Molecular understanding of water is challenging due to the structural complexity of liquid water and the large number of ice phases. Here the authors use a machine-learning potential trained on liquid water to demonstrate the structural similarity of liquid water and that of 54 real and hypothetical ice phases.

• Bartomeu Monserrat
• , Jan Gerit Brandenburg
•  & Bingqing Cheng
• Article
| Open Access

### How Rh surface breaks CO2 molecules under ambient pressure

Direct observation of carbon dioxide dissociation provides an origin of catalytic conversion for industrial chemical reactions. Here, the authors reveal their molecular interactions on the rhodium catalyst at near-ambient pressure by interface science techniques and computational calculations.

• Jeongjin Kim
• , Hyunwoo Ha
•  & Jeong Young Park
• Article
| Open Access

### Conformational disorder of organic cations tunes the charge carrier mobility in two-dimensional organic-inorganic perovskites

Understanding the correlation between molecular structure and properties of 2D hybrid perovskites is crucial for material design and device performance. Here, the authors reveal that conformation of organic cations in the inorganic cages has strong effects on charge mobility and broadband emission behaviour.

• Chuanzhao Li
• , Jin Yang
•  & Shuji Ye
• Article
| Open Access

### Machine learning in chemical reaction space

Application of machine-learning approaches to exploring chemical reaction networks is challenging due to need of including open-shell reaction intermediates. Here the authors introduce a density functional theory database of closed and open-shell molecules for machine-learning predictions of reaction energies.

• Sina Stocker
• , Gábor Csányi
•  & Johannes T. Margraf
• Article
| Open Access

### Infrared spectroscopic study of hydrogen bonding topologies in the smallest ice cube

Spectroscopic studies of water clusters provide insight into the hydrogen bond structure of water and ice. The authors measure infrared spectra of neutral water octamers using a threshold photoionization technique based on a tunable vacuum-UV free electron laser, identifying two cubic isomers in addition to those previously observed.

• Gang Li
• , Yang-Yang Zhang
•  & Ling Jiang
• Article
| Open Access

### Impact of wet-dry cycling on the phase behavior and compartmentalization properties of complex coacervates

Wet-dry cycling is thought to have enabled the production of molecular building blocks of life. Here, the authors investigate the impact of dehydration/rehydration on RNA-containing complex coacervates, which are membraneless compartments formed by phase separation of polyelectrolyte solutions.

• , Alexander E. Marras
•  & Christine D. Keating
• Article
| Open Access

### Reorientation-induced relaxation of free OH at the air/water interface revealed by ultrafast heterodyne-detected nonlinear spectroscopy

Water’s hydrogen-bond network is truncated at hydrophobic interfaces and the dynamics of the resulting free OH groups is not well understood. The authors experimentally show that the main vibrational relaxation mechanism for free OH at the air-water interface is a diffusive molecular reorientation, rather than intramolecular energy transfer.

• Ken-ichi Inoue
• , Mohammed Ahmed
•  & Tahei Tahara
• Article
| Open Access

### Sensitivity enhancement of homonuclear multidimensional NMR correlations for labile sites in proteins, polysaccharides, and nucleic acids

Here, the authors present an approach that enhances the sensitivity of basic 2D biomolecular NMR experiments like NOESY and TOCSY, when carried out in polysaccharides, proteins and nucleic acids. This method combines principles associated to quantum Anti-Zeno Effects and advanced data acquisition methods based on Hadamard multiplexing.

• Mihajlo Novakovic
• , Ēriks Kupče
•  & Lucio Frydman
• Article
| Open Access

### Electrification at water–hydrophobe interfaces

Electrification of water upon contact with hydrophobic surfaces is a ubiquitous but poorly understood phenomenon. Here, the authors pinpoint the factors responsible for the excess positive charge carried by water droplets dispensed from hydrophobic capillaries, thereby answering some outstanding questions and raising new ones.

• Jamilya Nauruzbayeva
• , Zhonghao Sun
•  & Himanshu Mishra
• Article
| Open Access

### Controlling the symmetry of inorganic ionic nanofilms with optical chirality

The symmetry of metal ions in inorganic nanofilms can be manipulated by the transfer of optical spin from a chiral light beam. Here the authors present a route to functional manipulation that does not require the application of extreme conditions.

• Christopher Kelly
• , Donald A. MacLaren
• Article
| Open Access

### Combinatorial entropy behaviour leads to range selective binding in ligand-receptor interactions

Multivalent ligand-receptor interactions enhance binding selectivity in biological systems, and may be exploited to design synthetic systems. Here the authors demonstrate a multivalent behavior where the ability to bind the target occurs when the receptor density is within a specific range.

• Meng Liu
• , Azzurra Apriceno
•  & Stefano Angioletti-Uberti
• Article
| Open Access

### Design of highly efficient deep-blue organic afterglow through guest sensitization and matrices rigidification

Though realizing organic materials with deep blue emission is attractive for next-generation display technologies, achieving this emission in afterglow molecules remains a challenge. Here, the authors report blue organic afterglow via a strategy involving guest sensitization and matrix rigidification.

• Shen Xu
• , Wu Wang
•  & Wei Huang
• Article
| Open Access

### Optical gap and fundamental gap of oligoynes and carbyne

Carbyne, a linear sp-hybridized carbon allotrope, is synthetically inaccessible and its properties are extrapolated from those of defined oligomers. Here the authors analyze weak optical bands in two series of oligoynes and reassess the optical and fundamental gap of carbyne to lower values than previously suggested.

• Johannes Zirzlmeier
• , Stephen Schrettl
•  & Holger Frauenrath
• Article
| Open Access

### Autonomous mesoscale positioning emerging from myelin filament self-organization and Marangoni flows

Buckling instabilities in amphiphile-based lamellar systems can lead to the formation of tubular fingers. Van der Weijden et al. show how to shepherd their growth and destination by using drain droplets that help establishing stable interconnected mesoscale droplet networks.

• Arno van der Weijden
• , Mitch Winkens
•  & Peter A. Korevaar
• Article
| Open Access

### Predicting heterogeneous ice nucleation with a data-driven approach

Heterogenous ice nucleation is a ubiquitous phenomenon, but predicting the ice nucleation ability of a substrate is challenging. Here the authors develop a machine-learning data-driven approach to predict the ice nucleation ability of substrates, which is based on four descriptors related to physical properties of the interface.

• Martin Fitzner
• , Philipp Pedevilla
•  & Angelos Michaelides
• Perspective
| Open Access

### Designing and understanding light-harvesting devices with machine learning

Photon-induced charge separation phenomena are at the heart of light-harvesting applications but challenging to be described by quantum mechanical models. Here the authors illustrate the potential of machine-learning approaches towards understanding the fundamental processes governing electronic excitations.

• Florian Häse
• , Loïc M. Roch
•  & Alán Aspuru-Guzik
• Article
| Open Access

### Probing the heterogeneous structure of eumelanin using ultrafast vibrational fingerprinting

Eumelanin protects cells from sun damage and is promising for energy conversion applications, but its structure and excited state dynamics are elusive. Here the authors shed light on both aspects combining selective excitation of UV- and visible-absorbing chromophores with time-resolved infrared spectroscopy.

• Christopher Grieco
• , Forrest R. Kohl
•  & Bern Kohler
• Article
| Open Access

### Chiroptical spectroscopy of a freely diffusing single nanoparticle

Chirality of nanostructures may be determined by ensemble measurements in solution or on single immobilized nanoparticles, with loss of detail or interference from the substrate. Here the authors demonstrate that circular differential scattering intensity spectra of freely diffusing single nanoparticles provide chiroptical spectra which reflect their intrinsic chirality.

• Johannes Sachs
• , Jan-Philipp Günther
•  & Peer Fischer
• Article
| Open Access

### Identification of molecular quantum states using phase-sensitive forces

The identification of molecular quantum states becomes challenging with increasing complexity of the molecular level structure. Here, the authors non-destructively identified excited molecular states of the $${{\rm{N}}}_{2}^{+}$$ ${\mathrm{N}}_{2}^{+}$ by interfering forces applied to both the molecular ion and to a co-trapped atomic ion.

• Kaveh Najafian
• , Ziv Meir
•  & Stefan Willitsch
• Article
| Open Access

### Site-dependent reactivity of MoS2 nanoparticles in hydrodesulfurization of thiophene

MoS2 nanoparticles catalyze the extraction of heteroatom S in hydrocarbons by adsorption onto S vacancies. Here, the authors show that S vacancy properties are highly site sensitive and that adsorption of thiophene leads to self-generation of a more open double vacancy site.

• Norberto Salazar
• , Srinivas Rangarajan
•  & Jeppe V. Lauritsen
• Article
| Open Access

### A leap in quantum efficiency through light harvesting in photoreceptor UVR8

Photoreceptor UVR8 in plants senses environmental UV levels through 26 structural tryptophan residues, but the role of 18 of them was unknown. The authors show, by experiments and computations, how these form a light-harvesting network that funnels the excitation to the pyramid centers enhancing the light-perception efficiency.

• Xiankun Li
• , Haisheng Ren
•  & Dongping Zhong
• Article
| Open Access

### Confinement in crystal lattice alters entire photocycle pathway of the Photoactive Yellow Protein

Protein structural dynamics can be studied by time-resolved crystallography (TRC) and ultrafast transient spectroscopic methods. Here, the authors perform electronic and vibrational transient absorption measurements to characterise the full photocycle of Photoactive Yellow Protein (PYP) both in the crystalline and solution state and find that the photocycle kinetics and structural intermediates of PYP deviate in the crystalline state, which must be taken into consideration when planning TRC experiments.

• Patrick E. Konold
• , Enis Arik
•  & Marie Louise Groot
• Article
| Open Access

### Room-temperature formation of CdS magic-size clusters in aqueous solutions assisted by primary amines

CdS magic-size clusters have, so far, been prepared only in organic solvents. Here, the authors report an aqueous-phase synthesis for CdS magic-size clusters at room temperature and reveal insights into the formation mechanism, including the key role of primary amines.

• Wushuang Wan
• , Meng Zhang
•  & Kui Yu
• Article
| Open Access

### Femtosecond X-ray emission study of the spin cross-over dynamics in haem proteins

The change from low-spin hexacoordinated to high-spin pentacoordinated domed form in heam upon ligand detachment and the reverse process underlie the respiratory function. The authors, using femtosecond time-resolved X-ray emission spectroscopy, capture the transient states connecting the two forms in myoglobin-NO upon NO photoinduced detachment.

• Dominik Kinschel
• , Camila Bacellar
•  & Majed Chergui
• Article
| Open Access

### Adsorption and activation of molecular oxygen over atomic copper(I/II) site on ceria

Precise control over the energy of atomic metal sites is key to unlocking novel reaction pathways. Here, the authors achieve selective oxygen activation by the isolated copper site on ceria, due to its reduced 3d orbital energy via cerium induced electron withdrawing effect.

• Liqun Kang
• , Bolun Wang
•  & Feng Ryan Wang
• Article
| Open Access

### as-Indaceno[3,2,1,8,7,6-ghijklm]terrylene as a near-infrared absorbing C70-fragment

The synthesis of hydrocarbons with attractive electronic structures remains challenging. Here, the authors describe the synthesis and properties of the C70 fragment as-indaceno[3,2,1,8,7,6-ghijklm]terrylene, which exhibits near-infrared (NIR) absorption.

• Yuki Tanaka
• , Norihito Fukui
•  & Hiroshi Shinokubo
• Article
| Open Access

### The electron affinity of astatine

Electron affinity (EA) is a key parameter in determining the chemical behavior of the elements, but challenging to measure for unstable atoms. Here the authors succeed in measuring the EA of astatine, the heaviest naturally occurring halogen, and compare it with predictions from relativistic calculations.

• David Leimbach
• , Julia Karls
•  & Sebastian Rothe
• Article
| Open Access

### Polypeptide formation in clusters of β-alanine amino acids by single ion impact

Formation of peptide bonds in cold gas-phase environments might represent a prebiotic synthesis route of polypeptides. Here, the authors show the formation of up to tetra-peptide species in the collision of He2+ ions, with kinetic energies typical for solar wind ions, with cold β-alanine clusters.

• Patrick Rousseau
• , Dariusz G. Piekarski
•  & Bernd A. Huber
• Article
| Open Access

### 3D-3D topotactic transformation in aluminophosphate molecular sieves and its implication in new zeolite structure generation

Zeolites have pore structures that are attractive for shape-selective catalysis and separation, but targeted synthesis is challenging. Here, the authors propose using a 3D-3D topotactic transformation to synthesize targeted zeolites, including some that may be not feasible with conventional methods.

• Zhehao Huang
• , Seungwan Seo
•  & Xiaodong Zou
• Article
| Open Access

### Imaging spatiotemporal evolution of molecules and active sites in zeolite catalyst during methanol-to-olefins reaction

Imaging zeolites in catalysis relies on the use of probe molecules or model catalysts. Here the authors show the synergy of a multiscale reaction-diffusion model and structured illumination microscopy to illustrate spatiotemporal evolution of molecules and acid sites in SAPO-34 zeolites in methanol-to-olefins reaction.

• Mingbin Gao
• , Hua Li
•  & Zhongmin Liu
• Article
| Open Access

### Observation of the geometric phase effect in the H+HD→H2+D reaction below the conical intersection

The geometric phase effect associated with a conical intersection between the ground and first excited electronic state has been predicted in the H3 system below the conical intersection energy. The authors, by a crossed molecular beam technique and quantum dynamic calculations, provide experimental evidence and insight into its origin.

• Daofu Yuan
• , Yin Huang
•  & Xueming Yang
• Article
| Open Access

### Detection of the thietane precursor in the UVA formation of the DNA 6-4 photoadduct

The mechanisms of formation of the (6-4) photoproducts in DNA damage by sunlight is still debated. Here the authors show, by optical spectroscopies and computations, the details of the formation of a (6-4) photoadduct via the thietane intermediate in a single-stranded DNA oligonucleotide.

• Luis A. Ortiz-Rodríguez
• , Christian Reichardt
•  & Carlos E. Crespo-Hernández
• Article
| Open Access

### Mapping the oxygen structure of γ-Al2O3 by high-field solid-state NMR spectroscopy

γ-Al2O3 is widely used in catalytic processes, but understanding its detailed structure remains a challenge. The authors, using two-dimensional solid-state NMR spectroscopy at a high magnetic field, characterize the spatial proximity and connectivity between oxygen species from the bulk to the surface.

• Qiang Wang
• , Wenzheng Li
•  & Feng Deng
• Article
| Open Access

### Direct observation of a Feshbach resonance by coincidence detection of ions and electrons in Penning ionization collisions

Here the authors use ion-electron coincidence imaging method to explore collision dynamics. They observe Feshbach resonance in the Penning ionization collision of argon and excited helium atoms, resulting in singly charged argon ion and ground state helium.

• Baruch Margulis
• , Julia Narevicius
•  & Edvardas Narevicius
• Article
| Open Access

### In situ observation of oscillatory redox dynamics of copper

How a catalyst behaves microscopically under reaction conditions, and what kinds of active sites transiently exist on its surface, is still very much a mystery to the scientific community. Here the authors report on in situ observation of a redox active copper catalyst by a combination of in situ imaging and spectroscopy tools.

• Jing Cao
• , Ali Rinaldi
•  & Marc Willinger
• Article
| Open Access

### π covalency in the halogen bond

Current models of halogen bonding describe the σ-symmetric component of this interaction but do not contemplate the possibility of π-covalency. Here the authors provide experimental and computational evidence of π-covalency in halogen bonds involving radical cation halogen bond donors.

• Cameron W. Kellett
• , Pierre Kennepohl
•  & Curtis P. Berlinguette
• Article
| Open Access

### Ultrafast diffusion exchange nuclear magnetic resonance

Analysis of exchange processes is time consuming by two-dimensional exchange NMR spectroscopy. Here the authors demonstrate a single-scan ultrafast Laplace NMR approach based on spatial encoding to measure molecular diffusion, with an increase by a factor six in the sensitivity per unit time.

• Otto Mankinen
•  & Ville-Veikko Telkki
• Article
| Open Access

### Uncovering the effects of interface-induced ordering of liquid on crystal growth using machine learning

Crystallization is a challenging process to model quantitatively. Here the authors use machine learning and atomistic simulations together to uncover the role of the liquid structure on the process of crystallization and derive a predictive kinetic model of crystal growth.

• Rodrigo Freitas
•  & Evan J. Reed
• Article
| Open Access

### Setting benchmarks for modelling gas–surface interactions using coherent control of rotational orientation states

A fundamental and predictive understanding of molecule-surface interactions is challenging to obtain. Here the authors report an experimental technique allowing direct measurement of the scattering matrix, which reports on the coherent evolution of quantum states of a molecule scattering from a surface.

• Yosef Alkoby