Chemical physics

  • Article
    | Open Access

    High-nitrogen content polyhedral molecules are of fundamental interest for theory and for synthesis applications. The authors, using isomer selective, tunable soft photoionization reflectron time-of-flight mass spectrometry, identify the formation of a hitherto elusive prismatic P3N3 molecule during sublimation of PH3 and N2 ice mixtures exposed to energetic electrons.

    • Cheng Zhu
    • , André K. Eckhardt
    •  & Ralf I. Kaiser
  • Article
    | Open Access

    Ultrafast diffraction is fundamental in capturing the structural dynamics of molecules. Here, the authors establish a variant of quantum state tomography for arbitrary degrees of freedom to characterize the molecular quantum states, which will enable the reconstruction of a quantum molecular movie from diffraction data.

    • Ming Zhang
    • , Shuqiao Zhang
    •  & Zheng Li
  • Article
    | Open Access

    Multistep nucleation phenomena are of considerable fundamental interest. Here the authors combine molecular dynamics, machine learning and molecular cluster analysis to investigate the multistep nucleation of smectic clusters from a nematic fluid that cannot be accounted for by the classical nucleation theory.

    • Kazuaki Z. Takahashi
    • , Takeshi Aoyagi
    •  & Jun-ichi Fukuda
  • Article
    | Open Access

    Shock-wave driven reactions of organic molecules may have played a key role in prebiotic chemistry, but their mechanisms are difficult to investigate. The authors, using time-resolved x-ray diffraction and small-angle x-ray scattering experiments, observe the transformation of liquid benzene during a shock, identifying carbon and hydrocarbon solid products.

    • D. M. Dattelbaum
    • , E. B. Watkins
    •  & R. L. Sandberg
  • Article
    | Open Access

    Radiationless relaxation is ubiquitous in natural processes and often involves excited states that are difficult to observe. Here the authors, combining X-ray transient absorption spectroscopy and computations, provide insight into the photoinduced dynamics in pyrazine and the involvement of an optically dark 1Au(nπ*) state.

    • Valeriu Scutelnic
    • , Shota Tsuru
    •  & Stephen R. Leone
  • Article
    | Open Access

    The roaming reaction is a common process in the gas phase and in solution, but observation of the involved atomic movements has been challenging. The authors, using femtosecond time-resolved X-ray liquidography, resolve the detailed structural dynamics at the onset of a roaming reaction in the photoinduced isomerization of BiI3 in solution.

    • Eun Hyuk Choi
    • , Jong Goo Kim
    •  & Hyotcherl Ihee
  • Article
    | Open Access

    Wear reduction in diamond-like carbon interacting with ZDDP-additivated oils is essential for current automotive applications. Here, the authors present an atomic-scale study revealing that this can be achieved by tailoring diamond-like carbon’s stiffness, surface nano-topography, and hydrogen content.

    • Valentin R. Salinas Ruiz
    • , Takuya Kuwahara
    •  & Maria-Isabel de Barros Bouchet
  • Article
    | Open Access

    The photodissociation dynamics of small molecules in the vacuum ultraviolet range can have key implications for astrochemical modelling, but revealing such dynamical details is a challenging task. Here the authors, combining high resolution experimental techniques, provide a detailed description of the fragmentation dynamics of selected rotational levels of a predissociated Rydberg state of H2S.

    • Yarui Zhao
    • , Zijie Luo
    •  & Xueming Yang
  • Article
    | Open Access

    The Jahn-Teller effect is the spontaneous symmetry breaking of the molecular structure caused by the coupling of electrons and nuclei. Here the authors use ultrafast Coulomb explosion imaging to map the evolution of the fundamental symmetry lowering process in photoionized methane within around 20fs.

    • Min Li
    • , Ming Zhang
    •  & Peixiang Lu
  • Article
    | Open Access

    Interatomic Coulombic decay, ICD, is commonly observed in systems weakly bound to different environments. Here the authors discuss the ICD in an electromagnetic cavity and show that the entanglement of atoms can change ICD rates substantially and be used to control the ICD process.

    • Lorenz S. Cederbaum
    •  & Alexander I. Kuleff
  • Article
    | Open Access

    Nuclear spin polarization and relaxation can be studied using nuclear magnetic resonance (NMR). Here the authors demonstrate a combination of fast-field cycling and optical magnetometry techniques, to realize a NMR sensor that operates in the region of very low frequency and high relaxation rate.

    • Sven Bodenstedt
    • , Morgan W. Mitchell
    •  & Michael C. D. Tayler
  • Article
    | Open Access

    Quantum-mechanical methods of benchmark quality are widely used for describing molecular interactions. The present work shows that interaction energies by CCSD(T) and DMC are not in consistent agreement for a set of polarizable supramolecules calling for cooperative efforts solving this conundrum.

    • Yasmine S. Al-Hamdani
    • , Péter R. Nagy
    •  & Alexandre Tkatchenko
  • Article
    | Open Access

    The H3+ ion plays a key role in interstellar chemistry and can be formed from organic compounds upon interaction with charged particles or radiation. Here the authors demonstrate that H3+ can also be formed from water adsorbed on silica nanoparticles exposed to intense laser pulses, conditions that mimic the impact of charged particles on dust in astrophysical settings.

    • M. Said Alghabra
    • , Rami Ali
    •  & Ali S. Alnaser
  • Article
    | Open Access

    Water’s phase diagram exhibits several hydrogen-disordered phases which become ordered upon cooling, but the behavior of ice VI is still debated. The authors, using high-pressure neutron diffraction, identify structural distortions that transform ice VI into ice XIX, here identified as a hydrogen disordered phase.

    • Christoph G. Salzmann
    • , John S. Loveday
    •  & Craig L. Bull
  • Article
    | Open Access

    Anisotropically functionalized colloids can serve as meso-atoms for self-assembly of new materials. Swinkels et al. extend the analogy with atomic scale counterparts and show how familiar ring opening and puckering emerges in alkane-like assemblies of tetraedric patchy particles.

    • P. J. M. Swinkels
    • , S. G. Stuij
    •  & P. Schall
  • Article
    | Open Access

    Methane is abundant in the Universe, is an important energy carrier and a model system for fundamental studies. Here, the authors measure the self-diffusion coefficient of supercritical methane at ambient temperature up to the freezing pressure, and find a different behavior than expected based on previous models.

    • Umbertoluca Ranieri
    • , Stefan Klotz
    •  & Livia E. Bove
  • Article
    | Open Access

    Sunlight can change the composition of atmospheric aerosol particles, but the mechanisms through which this happens are not well known. Here, the authors show that fast radical reaction and slow diffusion near viscous organic particle surfaces can cause oxygen depletion, radical trapping and humidity dependent oxidation.

    • Peter A. Alpert
    • , Jing Dou
    •  & Markus Ammann
  • Article
    | Open Access

    Understanding ice re-crystallization is key to improve the current cryopreservation technologies. Here, the authors bring together experiments and simulations to unravel the atomistic details of the ice re-crystallization inhibition (IRI) activity of poly(vinyl)alcohol—the most potent biomimetic IRI agent.

    • Fabienne Bachtiger
    • , Thomas R. Congdon
    •  & Gabriele C. Sosso
  • Article
    | Open Access

    Strong coupling of quantum emitters to plasmonic cavities allows exploring rich phenomenologies of light-matter interaction. Here, the authors report experiments on single colloidal quantum dots coupled to plasmonic metal nanostructures, revealing complex interactions between bright and dark states.

    • Satyendra Nath Gupta
    • , Ora Bitton
    •  & Gilad Haran
  • Article
    | Open Access

    Water ice exhibits several hydrogen-ordered and disordered phases and it’s unclear if a disordered phase can transform into only one ordered phase. Here, the authors identify a partially hydrogen-ordered phase at high pressure, ice XIX, as the second hydrogen-ordered phase of ice VI beside ice XV.

    • Ryo Yamane
    • , Kazuki Komatsu
    •  & Hiroyuki Kagi
  • Article
    | Open Access

    Water ice exhibits several hydrogen-disordered phases that become ordered upon lowering the temperature, but ordering of ice VI, one of the main ice phases, is not well understood. Here the authors identify and structurally refine a partially hydrogen-ordered phase, ice XIX, obtained from ice VI, and observe its transition to its partially hydrogen-ordered sibling ice XV.

    • Tobias M. Gasser
    • , Alexander V. Thoeny
    •  & Thomas Loerting
  • Article
    | Open Access

    The dissociation mechanism of the heme axial ligand in heme proteins is not yet fully understood. The authors investigate the photodissociation dynamics of the bond between heme Fe and methionine S in ferrous cytochrome c using femtosecond time-resolved X-ray solution scattering and X-ray emission spectroscopy, simultaneously tracking electronic and nuclear structure changes.

    • Marco E. Reinhard
    • , Michael W. Mara
    •  & Kelly J. Gaffney
  • Article
    | Open Access

    Colloidal rod-like mesogens make the study of liquid crystal structures available to simple optical microscopy. Wittmann et al. study topological defects in smectic phases under annular confinement and reveal a remarkable, quantitative agreement with a theoretic density functional description.

    • René Wittmann
    • , Louis B. G. Cortes
    •  & Dirk G. A. L. Aarts
  • Article
    | Open Access

    Molecular sieving typically occurs when molecules with smaller kinetic diameter than a nanopore selectively enter the pore. Here the authors show, using photoluminescence imaging and ab initio molecular dynamics simulations, that single-walled carbon nanotubes can separate n-hexane from cyclohexane, despite both having larger kinetic diameter than the nanopore.

    • Haoran Qu
    • , Archith Rayabharam
    •  & YuHuang Wang
  • Article
    | Open Access

    Here the authors report spectroscopy and dynamics of cavity coupled NO band of sodium nitroprusside using 2D infrared and transient spectroscopy employing pump-probe technique. They find signatures of third-order nonlinearity, incoherent and strong coupling effects of vibrational polaritons.

    • Andrea B. Grafton
    • , Adam D. Dunkelberger
    •  & Jeffrey C. Owrutsky
  • Article
    | Open Access

    High-level methods to describe van der Waals interactions are limited due to their computational cost. This work introduces a new theoretical approach, that extends the dipolar many-body dispersion formalism to higher-order contributions, demonstrated to be applicable to practically-relevant systems and nano-environments.

    • Martin Stöhr
    • , Mainak Sadhukhan
    •  & Alexandre Tkatchenko
  • Article
    | Open Access

    Solid hydrogen has increasingly hindered rotation under high pressure, but the effect on spin isomer populations had not been directly probed. Here the authors measure NMR spectra of solid hydrogen up to the megabar, and observe the crossover to a spin 1/2 dipolar system above 70 GPa where distinction between ortho and para spin isomers is lost.

    • Thomas Meier
    • , Dominique Laniel
    •  & Leonid Dubrovinsky
  • Article
    | Open Access

    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

    Crystallization-induced photoluminescence weakening in ultrasmall metal nanoparticles is not well understood. Here, the authors study conformational isomers of gold nanoclusters to examine the effect of interparticle distance on this phenomenon, and propose a model of distance-dependent non-radiative excitation electron transfer.

    • Zibao Gan
    • , Yungui Liu
    •  & Zhikun Wu
  • Article
    | Open Access

    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

    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

    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
    •  & Malcolm Kadodwala
  • Article
    | Open Access

    The origin of the covalent H–H bond is understood to be driven by kinetic energy lowering. Here the authors show this is not the case for bonds between heavier elements likely due to the presence of core electrons, and that constructive quantum interference instead drives bond formation.

    • Daniel S. Levine
    •  & Martin Head-Gordon
  • Article
    | Open Access

    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
  • Article
    | Open Access

    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

    Although adsorption of polymer chains at solid walls is well understood, their desorption has defied scrutiny so far. Cangialosi et al. use fast scanning calorimetry to rationalize the process before the high temperatures required for loosening the chains can break them apart.

    • Xavier Monnier
    • , Simone Napolitano
    •  & Daniele Cangialosi
  • Article
    | Open Access

    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

    Jamming and gelation constitute a longstanding challenge in materials science due to their out-of-equilibrium nature. Rouwhorst et al. show the hallmarks of a nonequilibrium phase transition in a tunable critical Casimir colloidal system, with critical exponents of cluster growth in agreement with percolation theory.

    • Joep Rouwhorst
    • , Christopher Ness
    •  & Peter Schall
  • Article
    | Open Access

    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
    • , Helen Chadwick
    •  & Gil Alexandrowicz
  • Article
    | Open Access

    Resolving concerted nuclear and electronic motion in real-time is a primary goal in chemistry. The authors monitor nuclear and valence electronic dynamics in the excited state single-bond isomerisation of a chromophore of photoactive yellow protein, using time-resolved photoelectron imaging and electronic structure calculations.

    • Cate S. Anstöter
    • , Basile F. E. Curchod
    •  & Jan R. R. Verlet
  • Article
    | Open Access

    Borospherenes are the boron-based analogs of fullerene cages. Here, the authors report a class of Ln3B18 metallo-borospherenes with unusual spherical trihedron geometry, in which the lanthanide atoms surprisingly form a part of the cage surface.

    • Teng-Teng Chen
    • , Wan-Lu Li
    •  & Lai-Sheng Wang
  • Article
    | Open Access

    Fast control over propulsion direction modulates interactions between self-propelled particles and opens new avenues for the design of active materials. Here, the authors present a light-active system that allows rapid direction reversal, leading to controlled fusion and fission of colloidal assemblies.

    • Hanumantha Rao Vutukuri
    • , Maciej Lisicki
    •  & Jan Vermant
  • Article
    | Open Access

    Autonomous control of liquid motion is vital to the development of new actuators and pumps in fluid systems but autonomous control of fluid motion is inaccessible in current systems. Here, the authors identify unique features of a photochromic molecular switch that enables its use for self-regulating light activated control of fluid flow.

    • Serena Seshadri
    • , Luke F. Gockowski
    •  & Megan T. Valentine