Papers by David Cappelletti
Physical chemistry chemical physics/PCCP. Physical chemistry chemical physics, 2024
This perspective review focuses on the results of an internally consistent study developed in the... more This perspective review focuses on the results of an internally consistent study developed in the Perugia laboratory, centered on the fundamental interaction components that, at large intermolecular distances, determine the formation of weak intermolecular hydrogen (HB) and halogen (XB) bonds. This investigation exploits old and novel molecular beam scattering experiments involving several gaseous prototypical systems. In particular, we focus on the kinetic energy dependence of the total (elastic + inelastic) integral cross-sections. Of particular interest is the measure of quantum interference patterns in the energy dependence of cross-sections of targeted systems and their shift compared to that of known reference systems. We interpreted these findings as interaction energy stabilization components, such as charge transfer, s-hole, and polar flattening, that emerge at intermediate separation distance ranges and selectively manifest for specific geometries of collision complexes. Another significant observable we discuss is the absolute value of the cross-section and its dependence on permanent multipole moments of the collisional partners. Specifically, we show how the spontaneous orientation of rotationally cold and polar molecules, due to the electric field gradient associated with the interaction between permanent multipole moments, can significantly modify the magnitude of the total crosssection, even at high values of the impact parameter. We are confident that the present results can help extend the force field formulation to various interacting systems and carry out molecular dynamics simulations under conditions of application interest.
Environmental Science and Pollution Research
Anthropogenic trace metal contamination has significantly increased and has caused many hazardous... more Anthropogenic trace metal contamination has significantly increased and has caused many hazardous consequences for the ecosystems and human health. The Terni basin valley (Central Italy) shows a heavy load of pollutants from industrial activities, while the characteristic orography structure of the valley favours air stagnation, thus limiting air pollution dispersal. The present study conducted in 2014 aimed to determine the concentration of ten metals in five species of butterflies at nine sites in the Terni valley along a 21-km-long transect, including both relatively pristine and industrial areas. At sites where soil contamination was high for a given metal, such as for chromium as in the case of site 4 (the closest to the steel plant) and for lead as in the case of site 2 (contaminated by a firing range), higher levels of contamination were observed in the tissues of butterflies. We found a correlation between soil contamination and the concentration of Cr, Al and Sr in the tiss...
Toxics
Insect pollinators provide an important ecosystem service that supports global biodiversity and e... more Insect pollinators provide an important ecosystem service that supports global biodiversity and environmental health. The study investigates the effects of the environmental matrix on six oxidative stress biomarkers in the honey bee Apis mellifera. Thirty-five apiaries located in urban, forested, and agricultural areas in Central Italy were sampled during the summer season. Enzyme activities in forager bees were analyzed using an artificial neural network, allowing the identification and representation of the apiary patterns in a Self-Organizing Map. The SOM nodes were correlated with the environmental parameters and tissue levels of eight heavy metals. The results indicated that the apiaries were not clustered according to their spatial distribution. Superoxide dismutase expressed a positive correlation with Cr and Mn concentrations; catalase with Zn, Mn, Fe, and daily maximum air temperature; glutathione S-transferase with Cr, Fe, and daily maximal air temperature; and glutathione...
Zenodo (CERN European Organization for Nuclear Research), Jan 23, 2023
AOD aerosol optical depth BC black carbon CCN cloud condensation nuclei CEACs chemicals of emergi... more AOD aerosol optical depth BC black carbon CCN cloud condensation nuclei CEACs chemicals of emerging Arctic concern CFCs chlorofluorocarbons eBC equivalent black carbon GC gas chromatograph
In this study, the anthropogenic contamination in Trasimeno lake (Central Italy) was investigated... more In this study, the anthropogenic contamination in Trasimeno lake (Central Italy) was investigated using three sediment cores of the last 150 years (Anthropocene) to identify the primary sources of pollutions and quantify the level of contaminant enrichment in the basin. To this aim, trace elements, polycyclic aromatic hydrocarbons, and lead isotope ratios have been determined at biannual resolution. The deeper parts of the sediment cores were used to estimate the local geochemical baseline, based on known statistical methods, and to determine the values of enrichment factors. Principal component analysis and factor analysis were exploited to associate chemical proxies to human-driven contamination processes. On these grounds it was possible to identify the timings and impacts of pre-world war industrial productions and more recent activities characteristic of the basin's surroundings, such as agriculture.
Aquatic Geochemistry, 2022
Lake systems are essential for the environment, the biosphere, and humans but are highly impacted... more Lake systems are essential for the environment, the biosphere, and humans but are highly impacted by anthropogenic activities accentuated by climate change. Understanding how lake ecosystems change due to human impacts and natural forces is crucial to managing their current state and possible future restoration. The high sensitivity of shallow closed lakes to natural and anthropogenic forcing makes these lacustrine ecosystems highly prone to variations in precipitation and sedimentation processes. These variation processes, occurring in the water column, produce geochemical markers or proxies recorded in lake sedimentary archives. This study investigated specific proxies on high-resolution sedimentary archives (2–3 years resolution) of the Trasimeno lake (Central Italy). The Trasimeno lake underwent three different hydrological phases during the twentieth century due to several fluctuations induced mainly by human activities and climate change. The Trasimeno lake, a large and shallo...
Atmospheric ice-nucleating particles (INPs) have substantial cloud-phase feedback, and ambient IN... more Atmospheric ice-nucleating particles (INPs) have substantial cloud-phase feedback, and ambient INP concentration may increase in the Arctic region in response to warming (Murray, Carslaw, and Field, 2020). Currently, there are limited INP observations in the Atlantic sector of the Arctic. With the goal of generating new ambient INP data in this particular region, we have measured and studied INP concentrations from Ny-Ålesund (Spitsbergen, Svalbard) during 2017-2019. More specifically, we collected aerosol particles on membrane filters at the Gruvebadet observatory (approx. 50 m above sea level), where a custom-built isokinetic laminar flow inlet is installed. Individual filters collected aerosol particles for 27 hours (at least) to several days with a constant sampling flow of less than 12.8 LPM, which was regulated by a critical orifice. Our sampling periods were intermittent, but covering all meteorological seasons overall. With these filter samples, we have conducted the offline...
The Journal of Chemical Physics, 2021
The interactions of He and Ne with propylene oxide have been investigated with the molecular beam... more The interactions of He and Ne with propylene oxide have been investigated with the molecular beam technique by measuring the total (elastic + inelastic) integral cross section as a function of collision velocity. Starting from the analysis of these experimental data, potential energy surfaces, formulated as a function of the separation distance and orientation of propylene oxide with respect to the interacting partners, have been built: The average depth of potential wells (located at intermediate separation distances) has been characterized by analyzing the observed “glory” quantum effects, and the strength of long-range attractions has been obtained from the magnitude and the velocity dependence of the smooth component of measured cross sections. The surfaces, tested and improved against new ab initio calculations of minima interaction energies at the complete basis set level of theory, are defined in the full space of relative configurations. This represents a crucial condition t...
Shallow and closed lakes are affected by meteorological and climate variations and are especially... more Shallow and closed lakes are affected by meteorological and climate variations and are especially sensitive to the change in their hydrological balance. In central Italy, there is the fourth-largest lake of the country, the Trasimeno Lake, whose water level has undergone various fluctuations over the centuries with alternation of flood and drought periods because of its shallow depth and the absence of natural outflows [1].
Environmental Pollution, 2021
We conducted a three-year campaign of atmospheric pollutant measurements exploiting portable inst... more We conducted a three-year campaign of atmospheric pollutant measurements exploiting portable instrumentation deployed on a mobile cabin of a public transport system. Size selected particulate matter (PM) and nitrogen monoxide (NO) were measured at high temporal and spatial resolution. The dataset was complemented with measurements of vehicular traffic counts and a comprehensive set of meteorological covariates. Pollutants showed a distinctive spatiotemporal structure in the urban environment. Spatiotemporal autocorrelations were analyzed by a hierarchical spatiotemporal statistical model. Specifically, particles smaller than 1.1 µm exhibited a robust temporal autocorrelation with those at the previous hour and tended to accumulate steadily during the week with a maximum on Fridays. The smallest particles (mean diameter 340 nm) showed a spatial correlation distance of ≈ 600 m. The spatial correlation distance reduces to ≈ 60 m for particle diameters larger than 1.1 µm, which also showed peaks at the stations correlated with the transport system itself. NO showed a temporal correlation comparable
Frontiers in Earth Science, 2021
We present a thorough evaluation of the water soluble fraction of the trace element composition (... more We present a thorough evaluation of the water soluble fraction of the trace element composition (Ca, Sr, Mg, Na, K, Li, B, Rb, U, Ni, Co, As, Cs, Cd, Mo, Se, Eu, Ba, V, Ge, Ga, Cr, Cr, P, Ti, Mn, Zr, Ce, Zn, Fe, Gd, Y, Pb, Bi, Yb, Al, Nb, Er, Nd, Dy, Sm, Ho, Th, La, Lu, Tm, Pr, Tb, Fe, In, Tl) and their fluxes in the annual snowpack and the firn of the Hansbreen (a tidewater glacier terminating in the Hornsund fjord, southwest Spitsbergen). The trace element samples were obtained from a 3 m deep snow pit dug at the plateau of the glacier (450 m a.s.l.), and from a 2 m deep firn core collected from the bottom of the snow pit. The comparison of elemental fluxes and enrichment factors allowed us to constrain specific summer and wintertime deposition patterns of water soluble trace elements in the southern part of the Svalbard archipelago. Our results suggest that the chemical composition of the Hansbreen (and likely other glaciers where the summit is close to the equilibrium line) is m...
The current inadequate understanding of ice nucleating particle (INP) sources in the Arctic regio... more The current inadequate understanding of ice nucleating particle (INP) sources in the Arctic region affects the 15 uncertainty in global radiative budgets and in regional climate predictions. In this study, we present atmospheric INP concentrations by offline analyses on samples collected at ground level in Ny-Ålesund (Svalbard), in spring and summer 2018. The ice nucleation properties of the samples were characterized by means of two offline instruments: the Dynamic Filter Processing Chamber (DFPC), detecting condensation freezing INPs, and the West Texas Cryogenic Refrigerator Applied to Freezing Test system (WT-CRAFT), measuring INPs by immersion freezing. 20 Both measurements agreed within an order of magnitude although with some notable offset. INP concentration measured by DFPC ranged 33-185 (median 88), 5-107 (50) and 3-66 (20) m-3 , for T =-22,-18 and-15°C, respectively, while at the same activation temperatures WT-CRAFT measured 3-199 (26), 1-34 (6) and 1-4 (2) m-3 , with an offset apparently dependent on the INP activation temperature. This observation may indicate a different sensitivity of Arctic INPs to different ice nucleation modes, even though a contribution from measurement and/or sampling uncertainties cannot be ruled out. 25 An increase in the coarse INP fraction was observed from spring to summer, particularly at the warmest temperature (up to ~70% at-15°C). This suggests a non-negligible contribution from local sources of biogenic aerosol particles. This conclusion is also supported by the INP temperature spectra, showing ice-forming activity at temperatures higher than-15°C. Contrary to recent works (e.g., INP measurements from Ny-Ålesund in 2012), our results do not show a sharp spring-to-summer increase of the INP concentration, with distinct behaviors for particles active in different temperature ranges. This likely indicates that 30 the inter-annual variability of conditions affecting the INP emission by local sources may be wider than previously considered and suggests a complex interplay between INP sources. This demonstrate the necessity of further data coverage.
Atmospheric Chemistry and Physics, 2021
In this study, we present atmospheric icenucleating particle (INP) concentrations from the Gruveb... more In this study, we present atmospheric icenucleating particle (INP) concentrations from the Gruvebadet (GVB) observatory in Ny-Ålesund (Svalbard). All aerosol particle sampling activities were conducted in April-August 2018. Ambient INP concentrations (nINP) were measured for aerosol particles collected on filter samples by means of two offline instruments: the Dynamic Filter Processing Chamber (DFPC) and the West Texas Cryogenic Refrigerator Applied to Freezing Test system (WT-CRAFT) to assess condensation and immersion freezing, respectively. DFPC measured nINPs for a set of filters collected through two size-segregated inlets: one for transmitting particulate matter of less than 1 µm (PM 1), the other for particles with an aerodynamic diameter of less than 10 µm aerodynamic diameter (PM 10). Overall, nINP PM 10 measured by DFPC at a water saturation ratio of 1.02 ranged from 3 to 185 m −3 at temperatures (T s) of −15 to −22 • C. On average, the supermicrometer INP (nINP PM 10 − nINP PM 1) accounted for approximately 20 %-30 % of nINP PM 10 in spring, increasing in summer to 45 % at −22 • C and 65 % at −15 • C. This increase in super-micrometer INP fraction towards summer suggests that super-micrometer aerosol particles play an important role as the source of INPs in the Arctic. For the same T range, WT-CRAFT measured 1 to 199 m −3. Although the two nINP datasets were in general agreement, a notable nINP offset was observed, particularly at −15 • C. Interestingly , the results of both DFPC and WT-CRAFT measurements did not show a sharp increase in nINP from spring to summer. While an increase was observed in a subset of our data (WT-CRAFT, between −18 and −21 • C), the spring-tosummer nINP enhancement ratios never exceeded a factor of 3. More evident seasonal variability was found, however, in our activated fraction (AF) data, calculated by scaling the measured nINP to the total aerosol particle concentration. In 2018, AF increased from spring to summer. This seasonal AF trend corresponds to the overall decrease in aerosol concentration towards summer and a concomitant increase in the contribution of super-micrometer particles. Indeed, the AF of coarse particles resulted markedly higher than that of submicrometer ones (2 orders of magnitude). Analysis of lowtraveling back-trajectories and meteorological conditions at GVB matched to our INP data suggests that the summertime INP population is influenced by both terrestrial (snow-free land) and marine sources. Our spatiotemporal analyses of satellite-retrieved chlorophyll a, as well as spatial source attribution, indicate that the maritime INPs at GVB may come from the seawaters surrounding the Svalbard archipelago and/or in proximity to Greenland and Iceland during the observation period. Nevertheless, further analyses, performed on larger datasets, would be necessary to reach firmer and more general conclusions.
Geophysical Research Letters, 2021
New particle formation in the Arctic atmosphere is an important source of aerosol particles. Unde... more New particle formation in the Arctic atmosphere is an important source of aerosol particles. Understanding the processes of Arctic secondary aerosol formation is crucial due to their significant impact on cloud properties and therefore Arctic amplification. We observed the molecular formation of new particles from low‐volatility vapors at two Arctic sites with differing surroundings. In Svalbard, sulfuric acid (SA) and methane sulfonic acid (MSA) contribute to the formation of secondary aerosol and to some extent to cloud condensation nuclei (CCN). This occurs via ion‐induced nucleation of SA and NH3 and subsequent growth by mainly SA and MSA condensation during springtime and highly oxygenated organic molecules during summertime. By contrast, in an ice‐covered region around Villum, we observed new particle formation driven by iodic acid but its concentration was insufficient to grow nucleated particles to CCN sizes. Our results provide new insight about sources and precursors of Ar...
Science of The Total Environment, 2021
Airborne bacteria were characterized over a 2-y period via high-throughput massive sequencing of ... more Airborne bacteria were characterized over a 2-y period via high-throughput massive sequencing of 16S rRNA gene in aerosol samples collected at a background mountain European Monitoring and Evaluation Programme (EMEP) Network site (Monte Martano, Italy) located in the Central Mediterranean area. The air mass origin of nineteen samples was identified by air mass modelling and a detailed chemical analysis was performed. Four main origins (Saharan, Northwestern , Northeastern , and Regional) were identified, and distinct microbial communities were associated with these air masses. Samples featured a great bacterial diversity with Protobacteria being the most abundant phylum, and Sphingomonas followed by Acidovorax, Acinetobacter and Stenotrophomonas the most abundant genera of the dataset. Bacterial genera including potential human and animal pathogens were more abundant in European and in Regional samples compared to Saharan samples; this stressed the relevance of anthropic impact on bacterial populations transported by air masses that cross densely populated areas. The principal aerosol chemical characteristics and the airborne bacterial communities were correlated by cluster analysis, similarity tests and non-metric multidimensional scaling analysis, explaining most of the variability observed. However, the strong correlation between bacterial community structure and air mass origin hampered the possibility to disentangle the effects of variations in bacterial populations and in dust provenance on variations in chemical variables.
Frontiers in Chemistry, 2019
Electric and magnetic field gradients, arising from sufficiently strong anisotropic intermolecula... more Electric and magnetic field gradients, arising from sufficiently strong anisotropic intermolecular forces, tend to induce molecular polarization which can often modify substantially the results of molecular collisions, especially at low rotational temperatures and low collision energies. The knowledge of these phenomena, today still not fully understood, is of general relevance for the control of the stereo-dynamics of elementary chemical-physical processes, involving neutral and ionic species under a variety of conditions. This paper reports on results obtained by combining information from scattering, spectroscopic and reactivity experiments, within a collaboration between the research groups in Perugia and Trento. We addressed particular attention to the reactions of small atomic ions with polar neutrals for their relevance in several environments, including interstellar medium, planetary atmospheres, and laboratory plasmas. In the case of ion-molecule reactions, alignment/orientation is a general phenomenon due to the electric field generated by the charged particle. Such phenomenon originates critical stereo-dynamic effects that can either suppress (when the orientation drives the collision complex into non-reactive or less reactive configurations), or enhance the reactivity (when orientation confines reagents in the most appropriate configuration for reaction). The associated rate coefficients show the propensity to follow an Arrhenius and a non-Arrhenius behavior, respectively.
Science of The Total Environment, 2020
The present paper describes the assessment of the atmospheric deposition processes in a basin val... more The present paper describes the assessment of the atmospheric deposition processes in a basin valley through a multidisciplinary approach based on the data collected within an extensive chemical-physical characterization of the soils, combined with the local meteorology. Surface soil cores were collected on a NNW-SSE transect across the Terni basin (Central Italy), between the Monti Martani and the Monti Sabini chains (956 m a.s.l.), featuring the heavily polluted urban and industrial enclave of Terni on its bottom. Airborne radiotracers, namely 210 Pb and 137 Cs, have been used to highlight atmospheric deposition. We observed an increased deposition flux of 210 Pb and 137 Cs at sites located at the highest altitudes, and the associated concentration profiles in soil allowed to evaluate the role of atmospheric deposition. We also obtained a comprehensive dataset of stable anthropogenic pollutants of atmospheric origin that showed heterogeneity along the transect. The behavior has been explained by the local characteristic of the soil, by seeder-feeder processes promoted by the atmospheric circulation, and was reconciled with the concentration profile of radiotracers by factor analysis. Finally, the substantial impact of the local industrial activities on soil profiles and the role of the planetary boundary layer has been discussed and supported by simulations employing a Lagrangian dispersion model. Soil plays a fundamental role in environmental biogeochemical cycling through a wide range of different processes, both naturally and anthropogenically driven. It is characterized by endogenous processes such as soil development, use, and management, as well as by exogenous processes e.g., climatic factors, atmospheric deposition, and runoff, which may add complexity in terms of chemical components transfer, mixing and reworking on not easily predictable space and time scales. As a result, soil behaves as a receptor for atmospheric deposition, reflecting the influence of atmospheric aerosols with the mediation of wet and, to a lesser extent, dry scavenging according to local climatology and pluviometric regime. Atmospheric deposition flux includes numerous chemical species from gas-to-particle reactions derived nutrients such as nitrate, ammonium, and sulfate, to metals, metalloids, and carbonaceous species (Vet et al., 2014a, b). Once deposited, substances may permeate and migrate to depth throughout the soil pores as a function of the relative interaction strength with soil components. Therefore, each atmospherically originated chemical species will produce a vertical concentration profile reflecting the interplay among its own physicochemical properties and soil properties. In particular, the mobility and adsorption processes of a pollutant in soil will depend on the soil mineralogical composition, porosity, water, and organic matter content, pH, and redox conditions. As time goes by, soil itself will evolve leading to temporal accretion and burial of older layers wherein both endogenous and exogenous substances can be stored and
Environmental Science and Pollution Research, 2019
We thank MIUR (Ministero dell'Istruzione, dell'Università e della Ricerca) and the Università deg... more We thank MIUR (Ministero dell'Istruzione, dell'Università e della Ricerca) and the Università degli 12 Studi di Perugia for financial support to the project AMIS, through the program "Dipartimenti di 13
Uploads
Papers by David Cappelletti