Article
Materials Science, Multidisciplinary
Lukas Graf, Martin Knupfer, Qingqing Wang, Mats Fahlman, Xianjie Liu
Summary: Two-dimensional, high-quality perylene single crystals were successfully grown using a space-confined strategy method. The films exhibited alpha form crystallization, which was confirmed through various techniques. The optical absorption measurements showed strong anisotropy and excellent agreement with literature data, while the field-effect transistor's anisotropic mobility data demonstrated high crystalline order. Momentum-dependent studies using electron energy-loss spectroscopy revealed negative dispersion of the first exciton along the crystal b direction, with an exciton bandwidth of 72 meV. The observed behavior is believed to be a result of charge-transfer exciton coupling between perylene dimers in the unit cell.
Article
Biochemistry & Molecular Biology
Francesco Segatta, David M. Rogers, Naomi T. Dyer, Ellen E. Guest, Zhuo Li, Hainam Do, Artur Nenov, Marco Garavelli, Jonathan D. Hirst
Summary: A fully quantitative theory on the relationship between protein conformation and optical spectroscopy would enhance understanding of protein dynamics and folding in biophysical and simulation studies. Recent advances in calculating near-UV bands, achieved through consideration of the vibrational structure of aromatic side chains, have improved accuracy in these calculations.
Article
Chemistry, Physical
Lars Mewes, Rebecca A. Ingle, Andre Al Haddad, Majed Chergui
Summary: Two-dimensional Fourier transform spectroscopy is a promising technique for studying ultrafast molecular dynamics, providing a more complete picture of dynamics with broadband laser pulses. This experiment presented visible broadband 2D spectra of dye molecules, revealing vibrational coherences and information about structural motion, and allowing for acquisition of 2D spectra with high bandwidth and temporal resolution.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Qizhou Chen, Yan Ho Kwok, Weijun Zhou, Guanhua Chen, Shaul Mukamel
Summary: A new time-domain simulation protocol for two-dimensional electronic spectra with photocurrent detection is presented in this study. Time-dependent density functional theory is applied to evaluate the photocurrent response, and a non-perturbative phase-matching approach is implemented to extract the fourth-order photocurrent signal. The simulations reveal resonant interactions between transition dipoles and incident pulses, and the identification of different sample-electrode couplings based on peaks/valleys in photocurrent spectra. Additionally, the qualitative reproduction of experimental spectra of a PbS quantum dot photocell shows stimulated electron dynamics.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Nikita Selivanov, Ruslan Kevorkyants, Alexei Emeline, Constantinos C. C. Stoumpos
Summary: In this study, the crystal and electronic structures of newly synthesized materials 3-NH3-PyPbX4 (X = Br, I) were investigated. Both compounds were found to be direct semiconductors with direct transitions occurring at specific k-points. The electronic states in the highest energy valence bands mainly originated from halogen anions, while the lowest states in the conduction band originated from lead orbitals. Additionally, the materials exhibited broad luminescence emissions, and two mechanisms of radiative relaxation were discussed.
Article
Chemistry, Physical
Dawei Kang, Xianghua Kong, Vincent Michaud-Rioux, Ying-Chih Chen, Zetian Mi, Hong Guo
Summary: The study introduces a DFT scheme to quantitatively predict band edge shifts and origins in aqueous 2D photocatalysts, revealing that the band edges are not rigidly shifted and explaining the phenomena through geometric deformation, water dipole, and charge redistribution effects. The upshift of CBM in aqueous MoS2 is found to thermodynamically assist carriers in the hydrogen evolution reaction, supporting its efficiency as a photocatalyst in experiments.
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Laura Vietze, Ellen H. G. Backus, Mischa Bonn, Maksim Grechko
Summary: In condensed molecular matter, low-frequency modes play a crucial role in determining thermodynamic parameters and functions, and can be measured directly using two-dimensional terahertz-infrared-visible spectroscopy. However, interference between signals from different excitation pathways may complicate the analysis of spectra.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Mikkel Bregnhoj, Helmut Lutz, Steven J. Roeters, Ingo Lieberwirth, Rolf Mertig, Tobias Weidner
Summary: Diatoms use silaffin peptides to synthesize titanium dioxide nanoparticles, providing an environmentally friendly approach for the production of nanomaterials with potential applications in water splitting and biocompatible materials design. The study demonstrates that the silaffin peptide R5 can precipitate stable titanium dioxide sheets.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
P. Wemhoff, N. Nilius, C. Noguera, J. Goniakowski
Summary: Researchers successfully synthesized and characterized a two-dimensional (V,Fe)(2)O-3 alloy supported on Pt(111), which exhibits thermodynamic stability at realistic temperatures. The preference for mixed V-Fe nearest-neighbor pairs formation was revealed through a combination of atomic-resolution STM experiments and DFT calculations. Monte Carlo simulations provided a detailed explanation of the observed cation distribution. The V-Fe mixing is restricted to 2D systems and is closely related to changes in vanadium oxidation state caused by substrate interactions.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Karin Fink, Sebastian Hoefener
Summary: The combination of wavefunction frozen-density embedding (FDE) with periodic repetition in one dimension is used in the KOALA program for molecular systems. This method allows for the calculation of local properties in condensed molecular systems by explicitly computing the electron density of the active subsystem. However, it does not yield orbital band structure, limiting its applicability to systems with metallic bonding.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Erik G. C. P. van Loon, Malte Schueler, Daniel Springer, Giorgio Sangiovanni, Jan M. M. Tomczak, Tim O. O. Wehling
Summary: Two-dimensional materials are influenced by their surroundings, and manipulating the dielectric screening can directly control the insulating state of Mott materials. Many-body calculations show spectroscopic changes and an insulator-to-metal transition through Coulomb engineering. We discuss the experimental conditions for achieving Coulomb engineering of Mott materials based on our proof-of-principle calculations.
NPJ 2D MATERIALS AND APPLICATIONS
(2023)
Article
Chemistry, Physical
Kritanjan Polley, Roger F. Loring
Summary: Thermofield dynamics is an accurate method for describing quantum mechanics at finite temperature, using a temperature-dependent quantum Hamiltonian to govern the wavefunction. The optimized mean trajectory (OMT) method allows for the calculation of spectroscopic response functions from trajectories generated by a classical mapping Hamiltonian. In this study, a thermofield OMT (TF-OMT) approach is developed by applying the OMT procedure to a temperature-dependent classical Hamiltonian determined from the thermofield-transformed quantum mapping Hamiltonian. Calculations of two-dimensional electronic and vibrational-electronic spectra demonstrate the close agreement between TF-OMT and OMT results.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Weixiang Kong, Xiaoliang Xiao, Wangping Xu, Rui Wang, Li-Yong Gan, Juan Wei, Jing Fan, Xiaozhi Wu
Summary: The study introduces a series of two-dimensional silicon carbides with a tetragonal lattice, exhibiting Dirac cones, which originate from a ring coupling mechanism. This mechanism also applies to other group IV binary compounds, indicating that two-dimensional tetragonal materials have the potential to produce Dirac cones.
Article
Spectroscopy
Isao Noda
Summary: A procedure is proposed to estimate pure component spectra from a limited number of available spectra, and it can handle systems with more than two component species.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Spectroscopy
Isao Noda
Summary: This paper explores the application of two-trace two-dimensional (2T2D) correlation analysis to multiple spectra, especially when the spectra are randomly collected without knowledge of the sampling order. The paper briefly reviews the calculation and interpretation of 2T2D correlation spectra, and describes a systematic procedure to identify characteristic bands that are mutually asynchronous and least overlapped. By applying 2T2D correlation to individual spectra using a representative reference spectrum, it is possible to obtain excellent estimates of the pure component spectra of the mixture.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2022)
Article
Chemistry, Analytical
Mattia Belotti, Mohsen M. T. El-Tahawy, Marco Garavelli, Michelle L. Coote, K. Swaminathan Iyer, Simone Ciampi
Summary: The study develops a direct, spatiotemporally resolved optical tracking method to detect and resolve convective disturbances in electrochemical reactivity. It is found that parasitic gas evolving reactions lead to overestimates of macroscopic diffusion coefficients by 10 times. A hypothesis is proposed linking large barriers to inner-sphere redox reactions to the formation of cation-rich overscreening and crowding double layer structures in imidazolium-based ionic liquids.
ANALYTICAL CHEMISTRY
(2023)
Article
Chemistry, Physical
Francesco Segatta, Daniel Aranda Ruiz, Flavia Aleotti, Martha Yaghoubi, Shaul Mukamel, Marco Garavelli, Fabrizio Santoro, Artur Nenov
Summary: This paper presents an accurate and efficient approach for calculating the linear and nonlinear optical spectroscopy of a closed quantum system. The method includes the effect of ultrafast nonadiabatic dynamics by numerically propagating the nuclear wave packet. The expressions for the evaluation of response functions are recast in a general form and validated using the multiconfiguration time-dependent Hartree method. The application to pyrene reveals the remarkable influence of ultrafast nonadiabatic dynamics on spectral line shapes.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Optics
Marco Piccardo, Michael de Oliveira, Veronica R. R. Policht, Mattia Russo, Benedetto Ardini, Matteo Corti, Gianluca Valentini, Jorge Vieira, Cristian Manzoni, Giulio Cerullo, Antonio Ambrosio
Summary: By introducing a diffractive axicon in a pulse shaper, topological-spectral correlation can be imparted to ultrafast pulses in the visible region with a large range of topological charges. This approach allows for the synthesis of ultrashort pulses with tailored spatial and temporal properties, enabling new possibilities in multimode photonics. The use of a diffractive axicon with circular geometry and a hyperspectral off-axis holography technique enables the control and manipulation of various properties of wave packets.
Article
Optics
Nicola Coluccelli, Giovanni Cichelli, Paolo Laporta, Giulio Cerullo
Summary: We propose a system that combines a high-energy femtosecond ytterbium laser, an optical parametric amplifier, and a photonic crystal hollow core fiber compressor for coherent anti-Stokes Raman scattering spectroscopy. The use of the compressor allows for matching the duration of the Stokes pulse to that of the pump pulse, resulting in improved excitation efficiency. Experimental results and a theoretical model are presented to quantify the expected sensitivity improvement. The system is successfully demonstrated for detecting bacterial spores on a surface with a single laser shot, achieving an unprecedented signal-to-noise ratio.
Article
Chemistry, Physical
Juliana Cuellar-Zuquin, Ana Julieta Pepino, Ignacio Fdez Galvan, Ivan Rivalta, Francesco Aquilante, Marco Garavelli, Roland Lindh, Javier Segarra-Marti
Summary: We characterized the photochemically relevant conical intersections between different DNA/RNA nucleobases using CASSCF algorithms. Our results show that the size of the active space significantly affects the conical intersection topographies, while the basis set size seems to have a minor effect. We ruled out structural changes as a key factor and highlighted the importance of accurately describing the electronic states involved in these intersections.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Nanoscience & Nanotechnology
Ana Senkic, Antonio Supina, Mert Akturk, Christoph Gadermaier, Margherita Maiuri, Giulio Cerullo, Natasa Vujicic
Summary: Using non-invasive techniques, we investigated the spatial distribution of defects in as-grown CVD MoS2 monolayers and found that increasing the growth temperature reduces the concentration of defects and changes their spatial distribution and type, leading to effects on the electronic and optical properties of the sample.
Article
Multidisciplinary Sciences
Charalambos Louca, Armando Genco, Salvatore Chiavazzo, Thomas P. Lyons, Sam Randerson, Chiara Trovatello, Peter Claronino, Rahul Jayaprakash, Xuerong Hu, James Howarth, Kenji Watanabe, Takashi Taniguchi, Stefano Dal Conte, Roman Gorbachev, David G. Lidzey, Giulio Cerullo, Oleksandr Kyriienko, Alexander I. Tartakovskii
Summary: Highly nonlinear excitonic and polaritonic effects are observed in bilayer MoS2 by employing hybridized interlayer excitons (hIX). The discovery of new types of excitonic species with strong inter-excitonic interactions provides new tools for studying few-polariton quantum correlations.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Kirsty E. McGhee, Michele Guizzardi, Rahul Jayaprakash, Kyriacos Georgiou, Till Jessewitsch, Ullrich Scherf, Giulio Cerullo, Anton Zasedatelev, Tersilla Virgili, Pavlos G. Lagoudakis, David G. Lidzey
Summary: This study proposes a new strategy for the ultrafast control of polariton resonances by modifying the optical cavity mode. The researchers successfully generated fully-reversible blueshifts of the lower polariton branch without reducing the exciton-photon coupling strength. This work has important applications in emerging computing technologies.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Physical
Henar Mateo-delaFuente, Davide Avagliano, Marco Garavelli, Juan J. Nogueira
Summary: The absorption and emission spectra of luciferine/luciferase were calculated using molecular dynamics simulations, hybrid quantum mechanics/molecular mechanics calculations, and transition density analysis. The presence of the enzyme hampers the torsional motion of the chromophore, reducing the intramolecular charge transfer nature of the absorbing and emitting state. However, a polar environment around the oxygen atom enhances the charge transfer character of the emitting state.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Proceedings Paper
Computer Science, Artificial Intelligence
Chiara Ceconello, Federico Vernuccio, Arianna Bresci, Francesco Manetti, Salvatore Sorrentino, Renzo Vanna, Giulio Cerullo, Dario Polli
Summary: Coherent anti-Stokes Raman scattering is a powerful technique for label-free vibrational imaging of biological samples. In this study, we demonstrate video-rate wide-field signal generation and acquisition for real-time investigation of fast biological dynamics. Our results pave the way for future clinical diagnostics applications with video-rate imaging capabilities.
HIGH-SPEED BIOMEDICAL IMAGING AND SPECTROSCOPY VIII
(2023)
Article
Materials Science, Multidisciplinary
Paolo Franceschini, Veronica R. Policht, Alessandra Milloch, Andrea Ronchi, Selene Mor, Simon Mellaerts, Wei -Fan Hsu, Stefania Pagliara, Gabriele Ferrini, Francesco Banfi, Michele Fabrizio, Mariela Menghini, Jean-Pierre Locquet, Stefano Dal Conte, Giulio Cerullo, Claudio Giannetti
Summary: In this study, we demonstrate coherent optical control of orbital occupation in V2O3, which determines the insulator-to-metal transition. Comparing experimental results with numerical solutions, we find that the electronic coherence time is approximately 5 fs. Temperature-dependent experiments also reveal an enhanced electronic coherence time near the critical temperature of the transition, emphasizing the role of fluctuations in determining electronic coherence. These findings provide new possibilities for selectively switching quantum materials' functionalities and coherently controlling solid-solid electronic transformations.
Article
Materials Science, Multidisciplinary
Giulia Folpini, Maurizia Palummo, Daniele Cortecchia, Luca Moretti, Giulio Cerullo, Annamaria Petrozza, Giacomo Giorgi, Ajay Ram Srimath Kandada
Summary: We investigate the effect of metal cation substition on the excitonic structure and dynamics in a prototypical Ruddlesden-Popper metal halide. Through an in-depth spectroscopic and theoretical analysis, we identify the presence of multiple resonances in the optical spectra of a phenethyl ammonium tin iodide, a tin-based RPMH. Based on ab initio calculations, we assign these resonances to distinct exciton series that originate from the splitting of the conduction band due to spin-orbit coupling. While the splitting energy in the tin based system is low enough to enable the observation of the higher lying exciton in the visible-range spectrum of the material, the higher splitting energy in the lead counterpart prevents the emergence of such a feature. We elucidate the critical role played by the higher lying excitonic state in the ultrafast carrier thermalization dynamics.
MATERIALS ADVANCES
(2023)
Article
Chemistry, Multidisciplinary
Yeonsig Nam, Huajing Song, Victor M. Freixas, Daniel Keefer, Sebastian Fernandez-Alberti, Jin Yong Lee, Marco Garavelli, Sergei Tretiak, Shaul Mukamel
Summary: Understanding conical intersection (CI) dynamics and subsequent conformational changes is crucial for exploring and controlling photo-reactions in aromatic molecules. In this study, we simulate the photoinduced S-3 to S-1 non-adiabatic dynamics of cyclooctatetraene (COT) and find good agreement with experimental relaxation times. We also investigate the potential of TRUECARS and TRXD to directly probe CI passages in COT, showing that these signals can sensitively monitor key chemical features and resolve ultrafast changes in aromaticity and geometries during the dynamics.
Review
Nanoscience & Nanotechnology
Andrea Schirato, Margherita Maiuri, Giulio Cerullo, Giuseppe Della Valle
Summary: Metallic nanostructures with localized surface plasmons (LSPs) provide unprecedented opportunities for advanced photonic materials and devices. The generation and relaxation processes of hot electrons in LSPs have been intensively studied, but their practical applications remain challenging due to the complexity and broad energy range involved. This paper reviews the authors' contribution to understanding ultrafast hot electron dynamics in plasmonic nanostructures, including experimental techniques, numerical modeling, and the design of novel optical functionalities enabled by ultrafast hot-electron dynamics.
Article
Chemistry, Multidisciplinary
Floriana Morabito, Kevin Synnatschke, Jake Dudley Mehew, Sebin Varghese, Charles James Sayers, Giulia Folpini, Annamaria Petrozza, Giulio Cerullo, Klaas-Jan Tielrooij, Jonathan Coleman, Valeria Nicolosi, Christoph Gadermaier
Summary: Liquid-phase exfoliation enables the production of nanosheet films of 2D semiconductors with exceptionally long carrier lifetime, which is suitable for applications such as light harvesting and sensing.
NANOSCALE ADVANCES
(2023)