Initial Chemical Composition Research Articles

Extending the Pre-ordered Precursor Reduction strategy to L10 ternary alloys: the case of MnFePt

L10 nanostructured alloys continue to attract a great deal of attention due to their advanced physico-chemical properties arising from the peculiar arrangement of the atoms in the tetragonal unit cell. Efforts have been focused on synthesizing and optimizing L10 3d-5d binary alloys, with the incorporation of a third element to enhance the chemical order degree and/or modulate the physical properties. Among the family members, magnetic L10 MnFePt ternary alloys are of great relevance owing to the possibility to tune the magnetic properties to meet the requirements of many applications including data storage/processing, sensors, catalysis, and biomedicine. In this work, a direct, effective and sustainable strategy, called Pre-ordered Precursor Reduction (PPR), was exploited for the first time to synthesize highly-ordered L10 MnFePt ternary alloy nanoparticles by thermal decomposition in reductive atmosphere of MnxFe1-x(H2O)6PtCl6 crystal salts whose crystallographic structure resembles the specific atomic arrangement of the L10 phase. Despite the higher complexity with respect to the binary system, the peculiar atomic arrangement of the elements in the precursor crystalline salt allows a great control over the structural and magnetic properties. By modulating the process conditions and the initial chemical composition it is possible to finely tune the magnetic properties thus proving the high versatility and efficiency of the PPR approach to synthesize highly ordered L10 ternary alloys with controlled properties.

Enhancing electric field intensity of interfacial electric double layer to improve properties of solid electrolyte interface for sodium-ion batteries

The electrical double layer (EDL) provides a critical area, where the specific adsorption on the electrode dominates the initial structure and chemical composition of the solid electrolyte interface (SEI) film. Therefore, the SEI can be optimized by adjusting the properties of the EDL. Here, we regulate the properties of EDL to optimize the composition and morphology of the SEI film on the hard carbon anode surface by adding NaF with small molecule structure. The preferential accumulation of NaF additives on the electrode surface enhances the electric field intensity and promotes electrolyte decomposition. That is, the formed SEI film rich in inorganic NaF and B-O components, can significantly improve the storage capacity of sodium ions in the hard carbon anode and accelerate the rapid transport of sodium ions. This strategy enables the cycling capacity to improve by 13.5 %, and maintain a stable capacity retention rate of 86.2 % at the rate of 1C after 500 cycles, thereby extending the lifespan and increasing the capacity of the rechargeable battery. The strategy that utilizing small molecule additives to enhance the electric field intensity of EDL provides a new approach to improve the performances of SEI film and battery performances.

Asteroseismology of the young open cluster NGC 2516

Context. Asteroseismic modelling of isolated stars presents significant challenges due to the difficulty in accurately determining stellar parameters, particularly the stellar age. These challenges can be overcome by observing stars in open clusters whose coeval members share an initial chemical composition. The light curves from the all-sky survey by the Transiting Exoplanet Survey Satellite (TESS) allow us to investigate and analyse stellar variations in clusters with an unprecedented level of detail for the first time. Aims. We aim to detect gravity-mode oscillations in the early-type main-sequence members of the young open cluster NGC 2516 to deduce their internal rotation rates. Methods. We selected the 301 member stars with no more than mild contamination as our sample. We analysed the full-frame image light curves, which provide nearly continuous observations in the first and third years of TESS monitoring. We also collected high-resolution spectra using the Fiber-fed Extended Range Optical Spectrograph for the g-mode pulsators, with the aim of assessing the Gaia effective temperatures and gravities and preparing for future seismic modelling. Results. By fitting the theoretical isochrones to the colour-magnitude diagram of a cluster, we determined an age of 102 ± 15 Myr and inferred that the extinction at 550 nm (A0) is 0.53 ± 0.04 mag. We identified 147 stars with surface-brightness modulations: 24 with gravity (g-)mode pulsations (γ Doradus or slowly pulsating B-type stars) and 35 with pressure (p-)mode pulsations (δ Sct stars). When sorted by colour index, the amplitude spectra of the δ Sct stars show a distinct ordering and reveal a discernible frequency-temperature relationship. The near-core rotation rates, measured from period spacing patterns in two slowly pulsating B-type (SPB) stars and nine γ Dor stars, reach up to 3 d−1. This is at the high end of the values found from Kepler data of field stars of similar variability type. The γ Dor stars of NGC 2516 have internal rotation rates as high as 50% of their critical value, whereas the SPB stars exhibit rotation rates close to their critical rate. Although the B-type stars are rotating rapidly, we did not find long-term brightness and colour variations in the mid-infrared, which suggests that there are no disc or shell formation events in our sample. We also discussed the results of our spectroscopic observations for the g-mode pulsators.

Investigation of the Properties of Anti-Friction Coatings Deposited with Different Casting Methods.

This article presents the research results of depositing anti-friction coatings (Babbitt) using three different casting methods: static casting, flame soldering, and clad welding. Babbitt alloy coatings deposited with different casting methods are discussed and explained in terms of changes in the coating properties, such as the microstructure, hardness, strength, and chemical composition. The results showed significant differences in the aforementioned properties, depending on the chosen coating deposition method. The results of the tests confirmed the importance of using shielding gas during deposition to ensure the chemical composition of the coating. The analysis revealed that decreases in the amounts of antimony and copper in the Babbitt coating compared with the initial concentrations were influenced by selective evaporation, oxidation, and the coating process parameters associated with different coating methods. To maintain the desired balance of mechanical properties in Babbitt coatings, it is important to control the antimony and copper contents. Clad welding deposition using a non-consumable tungsten electrode and argon shielding gas achieved a chemically stable coating quite close to the initial chemical composition of the Babbitt alloy.

INSPIRE: INvestigating Stellar Population In RElics – VI. The low-mass end slope of the stellar initial mass function and chemical composition

ABSTRACT The INSPIRE project has built the largest sample of ultra-compact massive galaxies (UCMGs) at 0.1 < z < 0.4 and obtained their star formation histories (SFHs). Due to their preserved very old stellar populations, relics are the perfect systems to constrain the earliest epochs of mass assembly in the Universe and the formation of massive early-type galaxies. The goal of this work is to investigate whether a correlation exists between the degree of relicness (DoR), quantifying the fraction of stellar mass formed at z > 2, and the other stellar population parameters. We use the Full-Index-Fitting method to fit the INSPIRE spectra to single stellar population (SSP) models. This allows us to measure, for the first time, the slope of the IMF, as well as stellar metallicity [M/H], [Mg/Fe], [Ti/Fe], and [Na/Fe] ratios, and study correlations between them and the DoR. Similarly to normal-sized galaxies, UCMGs with larger stellar masses have overall higher metallicities. We found a correlation between the IMF slope and the DoR, that, however, breaks down for systems with a more extended SFH. An even stronger dependency is found between the IMF and the fraction of mass formed at high-z. At equal velocity dispersion and metallicity, galaxies with a higher DoR have a larger dwarf-to-giant ratio, i.e. a bottom heavy IMF, than that of low-DoR counterparts. This might indicate that the cosmic epoch and therefore different formation scenarios influence the fragmentation of the star formation cloud and hence might be the explanation for IMF variations detected in massive ETGs.

Investigation of Phase Transformations and Ordering Mechanisms in a Pd–Cu–Ag–Ru Alloy

An in‐depth analysis of phase transformations in a Pd–Cu–Ag alloy, crucial for applications in hydrogen membranes and electrical components, is presented. The investigation emphasizes the influence of the deformation rate and addition of Ag on the formation of the ordered CuPd phase. This study focuses on a specific alloy composition, 49.1% Cu–41.3% Pd–8.3% Ag–1.3% Ru, investigating its behavior under various conditions. Through comprehensive analysis, including the influence of the initial state, deformation variations, and chemical composition modifications, high‐energy X‐ray diffraction to unveil detailed phase evolution dynamics is used. Surprisingly, experimental findings deviate from the anticipated phase diagram, uncovering a previously unrecognized three‐phase region with the formation of AgPd. Notably, the study reveals the pivotal role of the alloy's Ag content in the development of ordered CuPd and AgPd phases. The addition of Ru exhibits no involvement in the observed phase transformations, contributing to the understanding of the alloy's composition‐dependent behavior. This research provides valuable insights into the intricate interplay of factors influencing phase transformations, offering a nuanced perspective beyond theoretical predictions. The newfound understanding of Ag's role and Ru's inertness refines material design considerations, enhancing the grasp of the alloy's thermodynamic stability under varying conditions.

Impact of different approaches to computing rotating stellar models

Context. The physics of stellar rotation plays a crucial role in the evolution of stars, in their final fates, and for the properties of compact remnants. Aims. Diverse approaches have been adopted to incorporate the effects of rotation in stellar evolution models. This study seeks to explore the consequences that these various prescriptions for rotation have for the essential outputs of massive star models. Methods. We computed a grid of 15 and 60 M⊙ stellar evolution models with the Geneva Stellar Evolution Code that accounted for both hydrodynamical and magnetic instabilities induced by rotation. Results. In the 15 and 60 M⊙ models, the choice of the vertical and horizontal diffusion coefficients for the nonmagnetic models strongly impacts the evolution of the chemical structure, but has a weak impact on the angular momentum transport and the rotational velocity of the core. In the 15 M⊙ models, the choice of the diffusion coefficient impacts the convective core size during the core H-burning phase, regardless of whether the model begins core He-burning as a blue or red supergiant and regardless of the core mass at the end of He-burning. In the 60 M⊙ models, the evolution is dominated by mass loss and is less strongly affected by the choice of the diffusion coefficient. In the magnetic models, magnetic instability dominates the angular momentum transport, and these models are found to be less strongly mixed than their rotating nonmagnetic counterparts. Conclusions. Stellar models with the same initial mass, chemical composition, and rotation may exhibit diverse characteristics depending on the physics applied. By conducting thorough comparisons with observational features, we can ascertain which method(s) produce the most accurate results in different cases.

Crystal structure of Ti4Ni2C.

Single crystals of the inter-metallic phase with composition Ti4Ni2C were serendipitously obtained by high-pressure sinter-ing of a mixture with initial chemical composition Ti2Ni. The Ti4Ni2C phase crystallizes in the Fd m space group and can be considered as a partially filled Ti2Ni structure with the C atom occupying an octa-hedral void. Ti4Ni2C is isotypic with Ti4Ni2O, Nb4Ni2C and Ta4Ni2C, all of which were studied previously by means of powder diffraction.

Twenty red giants with magnetic fields: a detailed analysis of their chemical composition

ABSTRACT We determined the fundamental parameters and analysed the chemical composition for 20 G and K giants within 150 pc from the Sun, for which the magnetic fields Bmax from 0.3 to 98.6 G have been detected. Abundances of 18 chemical elements from lithium (Z = 3) to hafnium (Z = 72) are derived. From infrared CN molecular lines, the nitrogen abundance and the carbon isotope ratio 12C/13C are determined. The low values 12C/13C = 7–26 for most of the giants prove that they were passed through the deep convecting mixing during the first dredge-up (FDU) evolutionary phase. Lithium is detected in spectra of 16 of 20 giants studied. The presence of lithium in atmospheres of giants passed through the deep mixing during the FDU phase contradicts the theory. The pronounced correlation between the [N/C] and [N/O] values is found, which has an evolutionary nature. A comparison of this relation with theoretical models calculated for rotating stars shows that it reflects mainly the dependence of these two values on the initial rotational velocity. The total C + N + O abundance that should be constant during the star’s evolution is found to be correlated with [Fe/H]. This correlation can be explained partially by the known [O/Fe] versus [Fe/H] relation. The anticorrelation between the [El/Fe] and [Fe/H] values for rare earth (RE) elements is obtained. The relations for both the sum C + N + O and the RE elements reflect the initial chemical composition of the giants. No marked systematic differences in the element abundances are found between the magnetic and non-magnetic giants.

Effects of natural leaching on electronic properties of common lithium manganese oxide LiMn2O4

The effects of degradation and possible leaching of lithium in the natural conditions were tested by subjecting LiMn2O4 to 3-month degradation in an open air environment. The starting material was characterized structurally using X-ray (XRD) and neutron (NPD) powder diffraction and found to crystallize in the nominal Fd-3m space group. The initial chemical composition was verified using X-ray photoelectron spectroscopy (XPS), electron microscopy (EDS) and neutron prompt gamma activation analysis (PGAA). The effects of degradation were studied by reinvestigating the samples using XRD, XPS and X-ray absorption (XAS). The studies did not find any chemical shift of manganese caused by the removal of Li or any statistically significant degradation of the starting composition suggesting that the spinel cathode material is resistant to possible Li removal due to medium term natural exposure.

2D numerical modeling of solute transport Na-K from a geothermal reservoir: The case of Las Tres Vírgenes, BCS

Las Tres Vírgenes geothermal field (LTVGF) is located within the volcanic complex of the same name with temperatures between 250 and 275 °C and a total power generation capacity of 10 MW. For geothermal systems, understanding the thermodynamic-chemical equilibrium of the fluid-rock interaction allows us to study the reactions involved in the precipitation or dissolution of minerals. In this work, we use the hydrothermal alteration mineralogical phases albite, microcline, and zoisite that are in equilibrium with the geothermal fluid as a source of cations (Na+, K+, and Ca2+) to model the chemical composition of the geothermal fluids in the last 20 years. The heat transfer (conductive-convective) and solute transport (advective-diffusive) equations in 2D, were discretized using the Finite Volume Method (FVM) and were coupled to simulate the temperature profile and spatial distribution of the main cations in the LTVGF reservoir. The code evaluates the thermal and chemical evolution of the reservoir from an initial geothermal gradient and an initial chemical composition of the fluid to reach the present concentrations at reservoir conditions. Based on the model results, we consider a reservoir between 1000 and 2000 m in depth and initial concentrations of 100 ppm for sodium to get the average concentrations at reservoir conditions of wells LV-13, LV-11, LV-6, LV-3, LV-4, and LV-1 corresponding to values between 3138 and 3661 ppm and temperatures between 225 and 249 °C. For potassium, the initial concentration was 10 ppm to reproduce the average concentrations between 604 and 663 ppm for wells LV-13, LV-11, LV-4, and LV-5 obtaining temperatures between 223 °C and 257 °C. For calcium, the initial concentration was 2 ppm and reproduced the concentrations of wells LV-5 and LV-6 (251 and 260 ppm) which are at depths of 1737 and 2162 m and temperatures of 225 and 260 °C. This work presents perhaps the first approach to solute transport of the LTVGF reservoir and it was determined that the alteration minerals considered influence the chemical composition of the current discharge fluids of the field. These results promote using Na/K geothermometers based on ionic activities proposed in the literature to estimate the reservoir temperature according to the equilibrium conditions and the chemical composition of the fluids.

Impact of the uncertainties of 3α and 12C(α, γ)16O reactions on the He-burning phases of low- and intermediate-mass stars

Aims. We aim to estimate the impact on the stellar evolution of the uncertainties in the 3α and the 12C(α, γ)16O reaction rates, taking into account the recent improvements in their precision. Methods. We calculated models of low- and intermediate-mass stars for different values of 3α and 12C(α, γ)16O reaction rates. The 3α reaction rate was varied up to ±24% around the reference value, while the 12C(α, γ)16O reaction rate was varied by up to ±35%, taking into account different recent values for these quantities available in the literature. The models were calculated with the FRANEC evolutionary code for two different initial chemical compositions, namely, Y = 0.246, Z = 0.0001, and Y = 0.28, Z = 0.015 to represent different stellar populations. A M = 0.67 M⊙ model was chosen as representative of the first class (halo ancient stars), while for the second composition (disk stars), the M = 1.5 M⊙ and M = 2.5 M⊙ models were considered. The impact of 3α and 12C(α, γ)16O reaction rates on the central He-burning lifetime and the asymptotic giant branch (AGB) lifetime, as well as the mass of the C/O core at the central He exhaustion and the internal C and O abundances, was investigated. Results. A variation of the 12C(α, γ)16O reaction rates within its nominal error resulted in marginal differences in the analysed features among the three considered stellar masses, except for the C/O abundances. The central He-burning lifetime changed by less than 4%, while the AGB lifetime was affected only at the 1% level. The internal C and O abundances showed greater variation, with a change of about 15%. The uncertainty in the 3α reaction rate mainly influences the C and O central abundances (up to 10%) for all the models considered, and the AGB lifetime for intermediate mass stars (up to 5%). Most of the investigated features were affected by less than 2%. Conclusions. The current uncertainty in the explored reaction rates has a negligible effect on the predicted evolutionary time scale with respect to other uncertainty sources. On the other hand, the variability in the chemical profile left at the end of the shell He-burning phase is still relevant. We also checked that there is no interaction between the effects of the two reaction rates, as would be expected in the case of small perturbations.

New red giants in NGC 6791 and NGC 6819 using Kepler superstamps

Context. Stars that are members of stellar clusters are assumed to be formed at the same time and place from material with the same initial chemical composition. These additional constraints on the ensemble of cluster stars make these stars suitable as benchmarks. Aims. We aimed (1) to identify previously unknown red giants in the open clusters NGC 6791 and NGC 6819, (2) to extract their asteroseismic parameters, and (3) to determine their cluster membership. Methods. We followed a dedicated method based on difference imaging to extract the light curves of potential red giants in NGC 6791 and NGC 6819 from Kepler superstamp data. We extracted the asteroseismic parameters of the stars that showed solar-like oscillations. We performed an asteroseismic membership study to identify which of these stars are likely to be cluster members. Results. We found 149 red giant stars within the Kepler superstamps, 93 of which are likely cluster members. We were able to find 29 red giants that are not primary targets of Kepler, and therefore, their light curves had not been released previously. Five of these previously unknown red giants have a cluster membership probability greater than 95%.

Biosignature preparation for ocean worlds (BioPOW) instrument prototype

In situ sampling missions to detect biosignatures on ocean worlds requires thorough sample preparation to manage the expected chemical complexity of such environments. Proposed instruments must be capable of automatic liquid sample handling to ensure sensitive and accurate detections of biosignatures, regardless of the initial chemical composition. Herein, we outline the design, build, and test of the integrated Biosignature Preparation for Ocean Worlds (BioPOW) system capable of purifying amino acids from icy samples. This four step modular instrument 1) melts ice samples, 2) purifies amino acids via cation exchange chromatography, 3) concentrates via vacuum drying, and 4) derivatizes amino acids to volatilize and enable detection with downstream analytical instruments. Initial experiments validated the thermal performance of the system by melting ice in the sample cup (1 mL sample, 3°C–28°C, <5 min, 1.4 kJ) and heating the derivatization tank past the concentration temperature (20°C–60°C, 12 min, 3.6 kJ) to the derivatization temperature (60°C–90°C, 25 min, 7.5 kJ). Later experiments investigated important factors for automatic cation exchange using a design of experiments approach, and found that initial salt concentration, sample and eluate flow rates, and water wash volumes all play significant roles in reducing conductivity (1.1 x–6.7 x) while maintaining phenylalanine yields between 31% and 94%. The modules were then integrated into a 12 cm × 20 cm × 20 cm fieldable platform for analysis, and the maturation of this design for future spaceflight is discussed.

Al0.88Cu0.94Fe0.18.

The inter-metallic phase with composition Al0.88Cu0.94Fe0.18 was synthesized by high-temperature sinter-ing of a mixture with initial chemical composition Al78Cu48Fe13. Al0.88Cu0.94Fe0.18 adopts the CsCl structure type in space-group Pm m. The structure analysis revealed that one site is co-occupied by Al and Cu with a ratio of 0.88 (5):0.12 (5) and the other is co-occupied by Fe and Cu with a ratio of 0.2 (4):0.8 (4). The Al/Cu⋯Fe/Cu separation is 2.5465 (13) Å.

Mechanical and microstructural properties of iron mining tailings stabilized with alkali-activated binder produced from agro-industrial wastes

This study evaluated the stabilization of iron ore tailings (IOTs) with an alkali-activated binder (AAB) produced from sugar cane bagasse ash, hydrated eggshell lime, and sodium hydroxide solution. Unconfined compressive strength, split tensile strength, initial shear stiffness, mineralogy, chemical composition, and microstructure of IOTs-AAB were evaluated. Strength values up to 6.59 MPa were achieved after 28 days-curing at 40 °C. Reducing porosity and increasing the binder content improved the overall mechanical behavior. N-A-S-H like gels were identified in IOTs-AAB mixtures. Finally, longer curing times led to more compact structures.

The Use of Crystal Violet Degradation Products for Ballpoint Pen Ink Manuscript Dating.

Determining the approximate dates that written documents were drawn up based on the chemical composition of the ink is not a simple process. It is very demanding in terms of legal requirements. Various studies have succeeded in dating manuscripts by analyzing the temporal evolutions of the concentrations of dyes and solvents in documents based on the original formulations of the ink pens. These analyses were carried out simultaneously by HPLC-DAD for dyes and by GC-MS for solvents. This study aims, for the first time, to evaluate novel ink compounds and the temporal evolution of the concentrations of the degradation products of the dyes used by most suppliers and which are present in almost all types of ballpoint inks, i.e., Crystal Violet (CV). CV degrades through two parallel pathways: on the one hand, it undergoes progressive demethylation until it becomes pararosaniline, and on the other, it undergoes a breakdown of the molecule obtaining, among other by-products, the compound N,N'-Dimethyl-4-aminophenol (NNAPH), that was experimentally verified using four different inks (e.g., Inoxcrom® and Sigma® brands, in blue and black). For the NNAPH compound, we observed that four of the inks under analysis displayed the same temporary behavior despite having different initial chemical compositions. These initial results show the high potential for both CV and NNAPH, together with the rest of the pararosaniline family, as age tracers for dated/old documents. These techniques may potentially open up new avenues for universal dating tools, regardless of the brands of ink employed for use in different ballpoint pen types.

Microbial community attributes supersede plant and soil parameters in predicting fungal necromass decomposition rates in a 12-tree species common garden experiment

Although dead fungal mycelium (necromass) represents a key component of biogeochemical cycling in all terrestrial ecosystems, how different ecological factors interact to control necromass decomposition rates remains poorly understood. This study assessed how edaphic parameters, plant traits, and soil microbial community structure predicted the mass loss rates of different fungal necromasses within experimental monocultures of 12 tree species in Minnesota, USA. Necromass decay rates were most strongly driven by initial chemical composition, being significantly slower for fungal necromass with higher initial melanin content. Of the extrinsic ecological factors measured, variation in the amount of mass remaining for both low and high melanin necromass types was significantly predicted by soil bacterial richness and fungal community composition, but not by any soil microclimatic parameters or plant traits. Further, the microbial communities governing decay rates varied depending on the initial necromass chemical composition, suggesting that extrinsic and intrinsic factors interacted to propel decomposition. Finally, we also found significant positive relationships between the amount of remaining fungal necromass and soil carbon and nitrogen concentrations. Collectively, these results suggest that, after the initial chemical composition of dead fungal residues, soil microbial communities represent the main drivers of soil necromass degradation, with potentially large consequences for soil carbon sequestration and nutrient availability.

Exploring the origin of the extended main-sequence turn-off in M37 through the white dwarf cooling sequence

ABSTRACT We use new observations from the Canada–France–Hawaii Telescope to study the white dwarf cooling sequence of the open cluster M37, a cluster that displays an extended main-sequence turn-off and, according to a recent photometric analysis, also a spread of initial chemical composition. By taking advantage of a first epoch collected in 1999 with the same telescope, we have been able to calculate proper motions for sources as faint as g ∼ 26 (about ∼ 6 mag fainter than the Gaia limit), allowing us to separate cluster members from field stars. This has enabled us to isolate a sample of the white dwarf population of M37, reaching the end of the cooling sequence (at g ∼ 23.5). Here, the derived atlas and calibrated catalogue of the sources in the field of view is publicly released as supplementary online material. Finally, we present an exhaustive comparison of the white dwarf luminosity function with theoretical models, which has allowed us to exclude the age-spread scenario as the main responsible for the extended turn-off seen in the cluster colour–magnitude diagram.

The broadening of the main sequence in the open cluster M38

Abstract Our recent multi-band photometric study of the colour width of the lower main sequence of the open cluster M37 has revealed the presence of a sizeable initial chemical composition spread in the cluster. If initial chemical composition spreads are common amongst open clusters, this would have major implications for cluster formation models and the foundation of the chemical tagging technique. Here we present a study of the unevolved main sequence of the open cluster M38, employing Gaia DR3 photometry and astrometry, together with newly acquired Sloan photometry. We have analysed the distribution of the cluster’s lower main sequence stars with a differential colour-colour diagram made of combinations of Gaia and Sloan magnitudes, like in the study of M37. We employed synthetic stellar populations to reproduce the observed trend of M38 stars in this diagram, and found that the observed colour spreads can be explained simply by the combined effect of differential reddening across the face of the cluster and the presence of unresolved binaries. There is no need to include in the synthetic sample a spread of initial chemical composition as instead necessary to explain the main sequence of M37. Further photometric investigations like ours, as well as accurate differential spectroscopic analyses on large samples of open clusters, are necessary to understand whether chemical abundance spreads are common among the open cluster population.