Neutral Species Research Articles

Single-photon large-momentum-transfer atom interferometry scheme for Sr or Yb atoms with application to determining the fine-structure constant

The leading experimental determinations of the fine-structure constant α currently rely on atomic photon-recoil measurements from Ramsey-Bordé atom interferometry with large-momentum transfer to provide an absolute mass measurement. We propose an experimental scheme for an intermediate-scale differential atom interferometer to measure the photon recoil of neutral atomic species with a single-photon optical clock transition. We calculate trajectories for our scheme that optimize the recoil phase while nullifying the undesired gravity-gradient phase by considering independently launching two clouds of ultracold atoms with the appropriate initial conditions. For Sr and Yb, we find an atom interferometer of height 3 m to be sufficient for an absolute mass measurement precision of Δm/m∼1×10−11 with current technology. Such a precise measurement would halve the current uncertainty in α, an uncertainty that would no longer be limited by an absolute mass measurement. The removal of this limitation would allow the current uncertainty in α to be reduced by a factor of 10 by corresponding improvements in relative mass measurements, thus paving the way for higher-precision tests of the standard model of particle physics. Published by the American Physical Society 2024

Encapsulating Proton Inside C60 Fullerene: A Density Functional Theory Study on the Electronic Properties of Cationic X+@C60 (X+ = H+, H3O+ and NH4+)

Confining protons into an enclosed carbon cage is expected to give rise to unique electronic properties for both the inner proton and the outer cage. In this work, we systematically investigated the geometric and electronic structures of cationic X+@C60 (X+ = H+, H3O+, and NH4+), and their corresponding neutral species (X = H2O, NH3), by quantum chemical density functional theory calculations. We show that C60 can trap H2O, NH3, H3O+ and NH4+ at the cage center and only slightly influence their geometries. The single proton clings to the inner wall of C60, forming a C-H chemical bond. The encapsulated neutral species almost do not change the electronic structure of the C60, while the internal cations have obvious effects. The charge transfer effect from the inner species to the C60 cage was found for all X@C60 (X = H2O, NH3) (about 0.0 e), X+@C60 (X+ = H3O+, NH4+) (about 0.5 e) and H+@C60 (about 1.0 e) systems. Encapsulating different forms of protons also regulates the fundamental physico-chemical properties of the hollow C60, such as the HOMO-LUMO gaps, infrared spectra, and electrostatic potential, etc., which are discussed in detail. These findings provide a theoretical insight into protons’ applications, especially in energy.

Influence of Acylation by Hydroxycinnamic Acids on the Reversible and Irreversible Processes of Anthocyanins in Acidic to Basic Aqueous Solution.

In this work, the thermodynamics and kinetics of the reversible and irreversible processes of cyanidin 3,5-O-diglucoside and cyanidin 3-O-(2-O-glucosyl, 6-O-sinapoyl)glucoside-2-O-glucoside, 5-O-glucoside were studied by covering all pH range (holistic approach). The acylation (i) decreases the mole fraction of the colorless hemiketal in acidic medium and increases that of the colored quinoidal base, (ii) expands the pH domain of the flavylium cation, and (iii) moderately decreases the rate of tautomerization and isomerization of the neutral and monoanionic species. Degradation of cyanidin-3,5-O-diglucoside in a basic medium occurs in two distinct stages. After the formation of the anionic quinoidal bases (double proton loss from flavylium cation), a fast kinetic step, only observed by stopped flow, gives rise to the B4n- hydroxide adducts (n = 2,3) in equilibrium with the respective quinoidal bases An- (n = 1,2), leading to a first transient state. The quinoidal bases and B4n- adducts disappear completely from the first to a second transient state by means of two parallel reactions: (i) one reversible, giving the anionic cis- and trans-chalcones, (ii) the other irreversible, giving degradation products and exhibiting a pH-dependent bell-shaped mole fraction with maximum around pH = 12. From the second transient state, the anionic chalcones disappear completely in a few days. Acylation prevents formation of the first transient state. All of these effects are compatible with anthocyanidin-acyl π-stacking interactions (intramolecular copigmentation).

Transport properties of high Mach number hypersonic air plasmas

Abstract The collisional and transport properties of hypersonic plasmas have been simulated by an air plasma chemistry model, which includes collisions with electrons, ions and neutral species, elastic scattering, vibrational relaxation and a transport model. Species and thermal fluxes at the surface of the vehicle have been investigated as a function of post-shock gas temperature and species sticking coefficient for a fixed altitude of 50 km. At temperatures below about 5,000 K, the leading species are vibrationally excited nitrogen molecules, while at higher temperatures the molecular nitrogen and atomic oxygen dominate. Large fluxes of oxygen atoms have been observed in the simulations, on the order of 10^20 cm^-2s^ -1, which may lead to high rates of surface oxidation. Another subject of this study is temperature equilibration. For electrons, equilibration takes tens of microseconds, while the vibrational temperature equilibration time vary widely; from a few microseconds to hundreds of microseconds, depending on the gas temperature. Finally, the adiabatic parameter  was calculated for post-shock gas temperatures 5,000 K and 10,000 K and total gas density 1.2×10^17 cm^(-3). For post-shock gas temperature 5,000 K, only a slight reduction of gamma from the ideal gas value of ~1.4 is observed, while for 10,000 K it drops to ~1.26, which has a considerable impact on plasma properties. It was further established that the vibrational kinetics plays a leading role. While a single excited vibrational level of the N2 molecule captures the salient properties of the plasma, a detailed vibration kinetics is required for high-fidelity simulations.

Iron Selenide Intercalated by Uncharged Molecules: Superconductivity in FeSe(C2H7NO)0.3

AbstractThe charge‐neutral intercalated iron selenide compound FeSe(C2H7NO)0.3 is formed from FeSe(C2H8N2)0.3 through amine exchange under solvothermal conditions. Although the exchanged molecules are of similar size, the distance of the FeSe‐layers increases from 10.68 Å to 13.58 Å. The combination of X‐ray diffraction and DFT calculations suggests a chemically reasonable, albeit somewhat simplified, model for the orientation of the molecules between the FeSe‐layers, which interact via weak hydrogen bonds. The neutral guest species is unable to transfer charge to the FeSe layers, which remain electronically undoped. While the starting compound is non‐superconducting, the resulting product exhibits a transition to superconductivity at Tc=14 K. The topology of the calculated Fermi surface undergoes only minimal alteration with increased layer spacing, a change that is considerably less pronounced than that observed with electron doping. Our findings indicate that undoped FeSe layers become superconducting when the interlayer distance is sufficiently large, while the highest critical temperatures necessitate additional electron doping.

Comparative study of various molecular feature representations for solvation free energy predictions of neutral species

Predicting molecular properties with the help of Neural Networks is a common way to substitute or enhance comprehensive quantum-chemical calculations. One of the problems facing researchers is the choice of vectorization approach to representing the solvent and the solute for the estimator model. In this work, 10 different approaches have been investigated for both organic solute and solvent including vectorizers that relied on macroscopic parameters, functional groups classification, molecular graphs, or atomic coordinates. A variation of the Bag of Bonds approach called JustBonds, trained on the MNSol database, showed the best overall performance resulting in RMSD < 2 kcal/mol for the blind dataset that contains the solutes not presented in the training subset and < 1 kcal/mol on records from Solv@TUM database, which is close to contemporary continuum models. We have also demonstrated that the most important bags usually contain heteroatom and play a key role in the solvation process. Furthermore, the small role of solvent vectorization was demonstrated and revealed that approaches based on functional groups or macroscopic solvent parameters are often enough to efficiently represent solvent media.

Trait-based ecology, trait-free ecology, and in between.

Trait-based ecology has become a popular phrase. But all species have traits, and their contributions to ecological processes are governed by those traits. So then, is not all ecology trait-based? Actually, there do exist areas of ecology that are consciously trait-free, such as neutral theory and species abundance distributions. But much of ecology could be considered actually or potentially trait-based. A spectrum is described, from trait-free through trait-implicit and trait-explicit to trait-centric. Trait-centric ecology includes positioning ecological strategies along trait dimensions, with a view to inferring commonalities and to generalizing from species studied in more detail. Trait-explicit includes physiological and functional ecology, and areas of community ecology and ecosystem function that invoke traits. Trait-implicit topics are those where it is important that species are different, but formulations did not initially characterize the differences via traits. Subsequently, strands within these trait-implicit topics have often moved towards making use of species traits, so the boundary with trait-explicit is permeable. Trait-based ecology is productive because of the dialogue between understanding processes in detail, via traits that relate most closely, and generalizing across many species, via traits that can be compared widely. An enduring key question for trait-based ecology is which traits for which processes.

Biaryl Anion Radical Formation by Potassium Metal Reduction of Aryl Isocyanates and Triaryl Isocyanurates.

The potassium metal reduction of aryl isocyanates (aryl = phenyl, p-tolyl, 3,5-dimethylphenyl, 4-biphenylyl, and 1-naphthyl) in THF with 18-crown-6 or in HMPA results in the formation of the corresponding triaryl isocyanurate anion radicals. Continued exposure to potassium results in loss of the isocyanurate anion radical and the eventual formation of the respective biaryl anion radical. The 1,1'-binaphthyl anion radical is found to undergo a cyclodehydrogenation reaction, which leads to formation of the perylene anion radical. When authentic triaryl isocyanurates are reduced with metal, the heterocyclic ring undergoes fragmentation with elimination of carbon monoxide to produce a triarylbiuret dianion. This ring opening reaction is initiated by the two-electron reduction of the neutral isocyanurate species. The biaryl anion radical is formed when the biuret dianion is reduced further with metal. A possible mechanism for biaryl formation involves a heterolytic cleavage of an aryl C-N bond and release of an aryl radical once the triarylbiuret dianion is further reduced. A subsequent intermolecular reaction between two aryl radicals forms the corresponding biaryl, which can then be reduced to the anion radical. Notably, when a mixture of two different triaryl isocyanurate compounds is reduced in solution, the corresponding mixed biaryl anion radical is generated.

Theoretical Study on the Dissociation Mechanism of Thiophene in the UV Photoabsorption, Ionization, and Electron Attachment Processes

ABSTRACTA computational study on the intricate mechanism of thiophene ring‐fragmentation (TRF) in the UV photodissociation, dissociative ionization, and dissociative electron attachment process has been performed. The complete fragmentation process is studied using high level G4 composite method for neutral, cationic, and anionic species by elucidating a detailed mechanism for various reaction channels. The study shows that for neutral thiophene, the major pathway is the migration of H atom and subsequent fragmentation through a transition state yielding acetylene (HC≡CH) and H2C=C=S. However, for the thiophene cation, the acetylene (HC≡CH)+H2C=C=S+ channel is a two‐step and barrier less process. The onset of CH3+HC=C=C=S channel has been observed in both the thiophene cation and anion which was absent in the neutral analogue. Similarly, the onset of H2S+HC≡C—C≡CH channel has been found to operate only in the thiophene cation. Others, such as HCS and HS elimination channels have been found in all the species showing similar dissociation mechanism. For the thiophene anion, the TRF process is very much similar to that of thiophene cation. However, the reaction enthalpies of the various elimination channels in the anionic species are lower as compared to that of cationic species. During the study, the ionization energies and electron affinities of various molecules/radicals produced during the fragmentation process of thiophene were also computed.

Mobile Phase Contaminants Affect Neutral Lipid Analysis in LC-MS-Based Lipidomics Studies.

Lipidomics is a well-established field, enabled by modern liquid chromatography mass spectrometry (LC-MS) technology, rapidly generating large amounts of data. Lipid extracts derived from biological samples are complex, and most spectral features in LC-MS lipidomics data sets remain unidentified. In-depth analyses of commercial triacylglycerol, diacylglycerol, and cholesterol ester standards revealed the expected ammoniated and sodiated ions as well as five additional unidentified higher mass peaks with relatively high intensities. The identities and origin of these unknown peaks were investigated by modifying the chromatographic mobile-phase components and LC-MS source parameters. Tandem MS (MS/MS) of each unknown adduct peak yielded no lipid structural information, producing only an intense ion of the adducted species. The unknown adducts were identified as low-mass contaminants originating from methanol and isopropanol in the mobile phase. Each contaminant was determined to be an alkylated amine species using their monoisotopic masses to calculate molecular formulas. Analysis of bovine liver extract identified 33 neutral lipids with an additional 73 alkyl amine adducts. Analysis of LC-MS-grade methanol and isopropanol from different vendors revealed substantial alkylated amine contamination in one out of three different brands that were tested. Substituting solvents for ones with lower levels of alkyl amine contamination increased lipid annotations by 36.5% or 27.4%, depending on the vendor, and resulted in >2.5-fold increases in peak area for neutral lipid species without affecting polar lipid analysis. These findings demonstrate the importance of solvent selection and disclosure for lipidomics protocols and highlight some of the major challenges when comparing data between experiments.

Exploring chemical reactivity through a combined conceptual DFT and ELF topology approach.

In a proof-of-concept study, we explore how a combined approach using the topology of the electron localization function (ELF) and the condensed dual descriptor (DD) function can guide the optimal orientation between reactants and mimic the potential energy surfaces of molecular systems at the beginning of the chemical pathway. The DD has been chosen for its ability to evaluate the regioselectivity of neutral and soft species and to potentially mimic the interaction energy obtained from the mutual interactions between nucleophilic and electrophilic regions of the building blocks under perturbative theory. Our method has been illustrated with examples in which the optimal orientation of several systems can be successfully identified. The limitations of the presented model in predicting chemical reactivity are outlined in particular the influence of the selected condensation scheme.

Molecular H2 in silicate melts

A series of hydrothermal diamond anvil cell experiments was conducted to constrain the equilibrium distribution of molecular H2 between H2O-saturated sodium aluminosilicate melts and H2O at elevated temperatures (600–800 °C) and pressures (317–1265 MPa). The distribution of H2 between the silicate liquid and the aqueous fluid was achieved through real-time monitoring of the H-H stretching vibration under in situ conditions using Raman vibrational spectroscopy. Results show that the solubility of H2 in silicate melts saturated with H2O decreases as the temperature increases, with control exerted by the mole fraction of H2O in the melt. The dissolution of H2 in the hydrous silicate melts appears to follow Henrian behavior, resembling that of an inert, neutral non-polar species. To express species solubility as a function of temperature (T in K) an empirical equation was developed:ln Km/f = 11.4 (±1.3) *1000 / T (K) − 18.7 (±1.1)where Km/f is the equilibrium constant for the reaction H2(g) = H2(melt). This equation was derived by integrating data from the current and prior experimental studies that include silicate melts with varying H2O saturation levels. It should be deemed applicable within the temperature range of 600–1450 °C and pressures ranging from 0.3 to 3 GPa. The implications are extended into developing an understanding of the H partitioning between H2-rich atmospheres blanketing magma oceans in the early history of planetary bodies. For example, transferring H from primordial atmospheric envelopes to the interior of rocky exoplanets may be less efficient than previously believed, which should be considered in models of volatile retention. Experimental data also suggest that minimal amounts of solar nebula H2 are likely to dissolve in the molten surface of primitive objects in the protoplanetary disk (∼10−5 to 10−9 mol faction H2 in melt), contradicting the highly reducing conditions observed in chondrule mineral compositions.

Tea Prepared from Dried Cannabis: What Do We Drink?

Besides many other uses, dried Cannabis may be used for "tea" preparation. This study focused on a comprehensive characterization of an aqueous infusion prepared according to a common practice from three fairly different Cannabis cultivars. The transfer of 42 phytocannabinoids and 12 major bioactive compounds (flavonoids) into the infusion was investigated using UHPLC-HRMS/MS. Phytocannabinoid acids were transferred generally in a higher extent compared to their counterparts; in the case of Δ9-THC, it was only in the range of 0.4-1.9% of content in the Cannabis used. A dramatic increase of phytocannabinoids, mainly of the neutral species, occurred when cream was added during steeping, and the transfer of Δ9-THC into "tea" achieved a range of 53-64%. Under such conditions, drinking a 250 mL cup of such tea by a 70 kg person might lead to multiple exceedance of the Acute Reference Dose (ARfD), 1 μg/kg b.w., even in the case when using hemp with a Δ9-THC content below 1% in dry weight for preparation.

Double Spin with a Twist: Synthesis and Characterization of a Neutral Mixed-Valence Organic Stable Diradical.

A convenient design strategy opens access to neutral open-shell mixed-valence species via the redox transformation of charged stable precursors, i.e., the spiro-fused borate anions. We have implemented this strategy for the synthesis of the first neutral mixed-valence diradical: two neutral mixed-valence radical fragments were assembled via a twisted biphenyl bridge. The diradical is a crystalline solid obtained in almost quantitative yield by using a facile synthetic procedure. It is stable at room temperature in the triplet ground state with a very small singlet/triplet gap. This metal-free diradical can reversibly form five redox states. The diradical exhibits an intense IVCT band in the NIR region and can be assigned as a Class 2 Robin-Day MV (mixed valence) system with weakly interacting redox centers. Computations suggest that this diradical finds itself in a unique tug-of-war between two electron delocalization patterns, Kekulé and non-Kekulé, which gives rise to two geometric isomers that are close in energy but drastically different in spin distribution and polarity. Such bistable spin-systems should be intrinsically switchable and promising for the design of functional spin devices. The scope and limitations of the new redox-strategy for the neutral MV radicals were also tested on other types of spiro-fused borates, revealing structural factors responsible for the evolution from transient to persistent and then to stable radicals.

ThunderBoltz: an open-source direct simulation Monte Carlo Boltzmann solver for plasma transport, chemical kinetics, and 0D modeling

Abstract Plasma-neutral interactions, including reactive kinetics, are often either studied in 0D using ODE-based descriptions, or in multi-dimensional fluid or particle-based plasma codes. The latter case involves a complex assembly of procedures that are not always necessary to test effects of underlying physical models and mechanisms for particle-based descriptions. Here we present ThunderBoltz, a lightweight, publicly available 0D direct simulation Monte Carlo code designed to accommodate a generalized combination of species and arbitrary cross sections without the overhead of expensive field solves. It can produce electron, ion, and neutral velocity distributions in applied AC/DC E-field and/or static B-field scenarios. The code is built in the C++ standard library and includes a convenient Python interface that allows for input file generation (including compatibility with cross section data from the LXCat database), electron transport and reaction rate constant post-processing, input parameter constraint satisfaction, calculation scheduling, and diagnostic plotting. These codes can be accessed at the repository: https://github.com/lanl/ThunderBoltz. In this work we compare ThunderBoltz transport calculations against Bolsig+ calculations, benchmark test problems, and swarm experiment data, finding good agreement with all three in the appropriate field regimes. In addition, we present example use cases where the electron, ion, and background neutral particle species are self-consistently evolved to model the background kinetics, a feature that is absent in fixed-background Monte Carlo and n-term Boltzmann solvers. The latter functionality allows for the possibility of particle-based chemical kinetics simulations of the plasma and neutral species as a new alternative to ODE-based approaches.

From surface activation to microfluidic heat pipes: An innovative in-situ wafer level heterogenous bonding method

There has been considerable interest in low-temperature in-situ integration techniques for the fabrication of hetero-structured substrates and micro/nanosystems. This study presents a novel bonding approach that uses a water vapor-assisted surface activation strategy with neutral oxygen species (NOS). This method enables of highly efficient in-situ bonding process that utilizes the controllable and flexible environment to meet specific integration needs without exposure to the unstable ambient air. The NOS and water vapor increases hydroxyl groups, leading to smoother and more hydrophilic surfaces. The combined effects of NOS and the water vapor result in a larger bonded area ratio and significantly higher bonding energy compared to those activated by NOS alone. Meanwhile, the silicon oxide and quartz glass surfaces avoid being heavily electrically charged. This process thus achieved flawless silicon/quartz glass wafer bonding at 150 °C with a high bonding energy (∼4 J/m2) and Si/Si bonding pairs without any subsequent annealing voids. Then, the bonding pairs have been verified to have high reliability in extreme environments from −65 °C to 200 °C with no thermal-shocked cracks. The high-quality heterointerfaces could also withstand subsequent mechanical grinding and polishing for silicon-on-quartz glass (SOQ) fabrication. Moreover, a SOQ structured microfluidic heat pipe device was successfully fabricated based on the low-temperature in-situ heterogenous bonding. The robust heterointerfaces ensured non-leakage working during the heat dissipation. This facile and cost-effective bonding method is suitable for damage-free heterogeneous integration of active devices, micro/nanofluidic chips, and M/NEMS packaging. It has of great potential in fields such as biochemical analysis, quantum computing, and thermal sensing.

Biochar from malt residue: Toward a circular economy for sustainable fluoroquinolone removal in aqueous systems

Malt bagasse holds potential as a high-value material, contributing to a circular economy. Biochars were synthesized via pyrolysis (PC-500) and hydrothermal carbonization (HC-150), with one-pot activation using phosphoric acid. Additionally, PC-500 activated with H3PO4 was synthesized for comparison. Various analytical methods were used to characterize the materials. The PC-500 and PCA-500 samples exhibited higher degrees of carbonization, whereas the HC-150 sample retained its functional groups more effectively. Biochars showed higher porosity than biomass, with microspheres present in HC-150. Evaluations were conducted on the removal of fluoroquinolones from water using biochars. Maximum removal efficiency was obtained at pH 8, favoring neutral fluoroquinolone species with a Brønsted acid-base nature. The experimental outcomes were further rationalized by the computational calculation of the physicochemical properties of the adsorbates, in analogy with the structural activity relationship approach in medicinal chemistry. The pseudo-second-order kinetic model proved to be the most suitable for fitting the experimental data, while the Langmuir model effectively described the adsorption isotherms. Ciprofloxacin, enrofloxacin, and norfloxacin showed maximum adsorption capacities (qmax) of 95, 164, and 99 mg g−1, respectively, when HC-150 was used. On the other hand, with PC-500, qmax of 57, 12, and 20 mg g−1 were obtained for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. Although PCA-500 enhanced adsorption capacity compared to PC-500, the qmax remained lower than the results obtained with HC-500, measuring at 51, 102, and 95 mg g−1. These findings emphasize malt bagasse biochar as a viable adsorbent.

Oxidation of Weakly Interacting Diradicals: An Approach for Strong and Tunable Near-Infrared-Absorbing Dyes Based on Small Chromophores.

Near-infrared (NIR)-absorbing dyes are valuable for various applications, such as bioimaging and electronic devices. This work introduces a novel approach for designing NIR dyes, oxidation of weakly coupled diradicals. Our approach features a weak exchange interaction in diradicals, which potentially leads to bonding/antibonding molecular orbitals with a small energy gap. We found that removing one of two singly occupied molecular orbital electrons of the diradicals results in an exceptionally narrow frontier orbital energy gap. We examined a series of Blatter radical dimers, and the most weakly coupled diradical prepared in this work (ΔEST ∼ 0.12 eV) with a molecular weight of 590 Da exhibited a strong NIR absorption band reaching 2200 nm upon one-electron oxidation. The optical band gaps of the radical cations strongly correlate to the exchange interaction in the precursor neutral species, offering prediction and fine-tuning of the optical band gap in the NIR region.

Comparative Study of Neutral and Cationic Sn2H2: Toward Laboratory Detection of the Cation.

Group 14 M2H2 isomers (M = Si, Ge, Sn, and Pb) have attracted interest due to their radically differing electronic structures from acetylene. To better understand the Sn-H interactions of the neutral and cationic Sn2H2 structures, we present the most rigorous study of these systems to date. CCSD(T)/cc-pwCVTZ harmonic frequencies are presented as the first predictions for the neutral and cationic species to date. CCSDT(Q)/CBS relative energies are reported using the focal point approach, confirming the butterfly isomer as the global minimum on the potential energy surface for both the neutral and cationic species. In all, there exist 7 minima and 15 transition states. NBO analysis is also performed to elucidate the changes in bond order going from neutral to cation across all isomers of Sn2H2. Our results provide insights into the important Sn-H interaction and provide guidance for future work that may detect in the laboratory for the first time.

Energy and spectroscopic parameters of neutral and cations isomers of the CnH2 (n = 2-6) families using high-level ab-initio approaches.

Cationic species, previously detected from ion-induced desorption of solid methane by plasma desorption mass spectrometry (PDMS), and neutral species, are investigated using high-level ab-initio approaches. From a set of 25 cationic and 26 neutral structures belonging to CnH2 (n = 2-6) families, it was obtained the energy, rotational constants, harmonic vibrational frequency, charge distribution and excitation energies. The ZPVE-corrected energies, at CCSD(T)-F12; CCSD(T)-F12/RI/(cc-pVTZ-F12, cc-pVTZ-F12-CABS, cc-pVQZ/C) (n = 2-5) and CCSD(T)/cc-pVTZ (n = 6) levels, reveal that the topology of the most stable isomer vary with n and the charge. Out of 674 harmonic frequencies, those with maximum intensity are generally in the 3000-3500 cm-1 range. Analysis of 169 vertical transition energies calculated with the EOM-CCSD approach, suggest three C6H2 species as potential carriers of the diffuse interstellar bands (DIB). Systematic comparison of properties between neutral and cationic species can assist in the structural description of complex matrices.