13 research outputs found
Quantum Chemical Modeling of the Photoinduced Activity of Multichromophoric Biosystems
No full textMultichromophoric biosystems represent a broad family with very diverse members, ranging from light-harvesting pigment-protein complexes to nucleic acids. The former are designed to capture, harvest, efficiently transport, and transform energy from sunlight for photosynthesis, while the latter should dissipate the absorbed radiation as quickly as possible to prevent photodamages and corruption of the carried genetic information. Because of the unique electronic and structural characteristics, the modeling of their photoinduced activity is a real challenge. Numerous approaches have been devised building on the theoretical development achieved for single chromophores and on model Hamiltonians that capture the essential features of the system. Still, a question remains: is a general strategy for the accurate modeling of multichromophoric systems possible? By using a quantum chemical point of view, here we review the advancements developed so far highlighting differences and similarities with the single chromophore treatment. Finally, we outline the important limitations and challenges that still need to be tackled to reach a complete and accurate picture of their photoinduced properties and dynamics
Il potenziale ruolo della creatività nel benessere psicologico dell’anziano: proposta di un training per favorire un invecchiamento attivo
No full textL’obiettivo dello studio è di indagare il possibile ruolo della creatività nella promozione di un invecchiamento
attivo attraverso un training che stimoli e potenzi le abilità di pensiero divergente. A tale scopo sono stati indagati
il benessere psicologico ed il funzionamento cognitivo su un campione di soggetti anziani prima e dopo la
partecipazione al training e a distanza di tre mesi dalla fine del training
Vitellogenin conservation in sea turtles: Anti-VTG antibody in Chelonia mydas VS. Caretta caretta
No full textVitellogenin (VTG) is considered as a marker of endocrine
disruption. A Western blot method for VTG quantification in
Caretta caretta turtle plasma was developed using anti-VTG
antibody for Chelonia mydas. A screening of samples (np
61) collected in the southern Mediterranean Sea around Lampedusa
Island, Italy, was performed. The antibody showed a
good cross-reactivity with C. caretta VTG, suggesting a certain
conservation of the core of the protein in different sea turtle
species. The optimal operative condition forWestern blot analysis
consists of using diluted plasma at 1 : 50. In field samples,
a certain mismatch with morphological sexing was observed,
and VTG was detected in young animals. These results suggest
the possibility of a precocious activation of VTG-encoding
genes before sexual maturation and/or exposure to endocrine
disrupter substances
Gestione del rischio e decision making: il ruolo della creatività
No full textLa gestione del rischio è un aspetto cruciale in tutte le fasi del ciclo di vita poiché è legata alla capacità di prendere decisioni in maniera funzionale. Questo diventa ancora più importante in età adulta e anziana, quando ci si trova ad affrontare più frequentemente situazioni che richiedono l’assunzione di rischi. Il contributo presenta i risultati di due studi. Il primo, condotto su 185 soggetti italiani sani (18-81 anni; M=39.9; DS=17.8), presenta i dati relativi alla relazione tra propensione al rischio (Domain-Specific Risk-Taking), stili di decisione (General Decision Making Style) e creatività
In Silico Ultrafast Nonlinear Spectroscopy Meets Experiments: The Case of Perylene Bisimide Dye
No full textSpectroscopy simulations are of paramount importance for the interpretation of experimental electronic spectra, the disentangling of overlapping spectral features, and the tracing of the microscopic origin of the observed signals. Linear and nonlinear simulations are based on the results drawn from electronic structure calculations that provide the necessary parameterization of the molecular systems probed by light. Here, we investigate the applicability of excited-state properties obtained from linear-response time-dependent density functional theory (TDDFT) in the description of nonlinear spectra by employing the pseudowavefunction approach and compare them with benchmarks from highly accurate RASSCF/RASPT2 calculations and with high temporal resolution experimental results. As a test case, we consider the prediction of femtosecond transient absorption and two-dimensional electronic spectroscopy of a perylene bisimide dye in solution. We find that experimental signals are well reproduced by both theoretical approaches, showing that the computationally cheaper TDDFT can be a suitable option for the simulation of nonlinear spectroscopy of molecular systems that are too large to be treated with higher-level RASSCF/RASPT2 methods
Characterization of the hemithioindigo photoswitch and its derivatives with x-ray photoabsorption and photoemission spectroscopies
No full textIn this study, we investigate the electronic structure of hemithioindigo–hemistilbene (HTI) photoswitches and their functionalized derivatives, HTI-OMe and HTI-SMe, using x-ray photoemission spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS) spectroscopy. HTI compounds are known for their high quantum yield, thermal bistability, and rapid photoisomerization, making them promising candidates for applications in molecular motors, optical materials, and photocatalysis. Our analysis, supported by first-principles simulations, reveals how the conjugation of heteroatoms within the π-system affects the core-level chemical shifts and ionization intensities in XPS, while NEXAFS probes the influence of substituents on virtual molecular orbitals and energy transitions. In particular, the comparison between different functionalized HTIs allowed us to evaluate the effect of electronic relaxation following core-level photoionization and photo-excitation. These results provide a detailed understanding of the influence of functionalization on the electron distribution of HTI compounds, providing a robust foundation for the study and control of ultrafast charge transfer and photoswitching mechanisms in these molecular systems
The Role of Creativity in Risk Management and Decision Making
No full textThe following research aims to present data from two studies conducted to investigate the relationship
between risk management as a style and during a task in a risky situation and creativity in ageing. Risk management is a crucial aspect at all stages of life, as it is linked to the ability to make decisions functionally. This aspect becomes more critical in adulthood and old age when one is often faced with situations requiring risk-taking
Modern quantum chemistry with [open]molcas
No full textMOLCAS/OpenMolcas is an ab initio electronic structure program providing a large set of computational methods from Hartree-Fock and density functional theory to various implementations of multiconfigurational theory. This article provides a comprehensive overview of the main features of the code, specifically reviewing the use of the code in previously reported chemical applications as well as more recent applications including the calculation of magnetic properties from optimized density matrix renormalization group wave functions
UV-Light-Induced Vibrational Coherences: The Key to Understand Kasha Rule Violation in <i>trans</i>-Azobenzene
No full textWe
combine sub-20 fs transient absorption spectroscopy with state-of-the-art
computations to study the ultrafast photoinduced dynamics of trans-azobenzene (AB). We are able to resolve the lifetime
of the ππ* state, whose decay within ca. 50 fs is correlated
to the buildup of the nπ* population and to the emergence of
coherences in the dynamics, to date unobserved. Nonlinear spectroscopy
simulations call for the CNN in-plane bendings as the active modes
in the subps photoinduced coherent dynamics out of the ππ*
state. Radiative to kinetic energy transfer into these modes drives
the system to a high-energy planar nπ*/ground state conical
intersection, inaccessible upon direct excitation of the nπ*
state, that triggers an ultrafast (0.45 ps) nonproductive decay of
the nπ* state and is thus responsible for the observed Kasha
rule violation in UV excited trans-AB. On the other
hand, cis-AB is built only after intramolecular vibrational energy
redistribution and population of the NN torsional mode
The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry
No full textThe developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations
