Effect of radiative cooling on the size-dependent stability of small boron clusters

Ferrari, Piero; Vanbuel, Jan; Hansen, Klavs; Lievens, Peter; Janssens, Ewald; Fielicke, André

doi:10.1103/physreva.98.012501

Cited by 15 publications

(9 citation statements)

References 28 publications

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“…Boron clusters are the main topic of several review articles and books [1,19,21,25,38], therefore, in this review only the basic information on boron clusters is provided; however, a little detail is given about their applications in medical field.…”

Section: Boron Clusters For Medical Applicationsmentioning

confidence: 99%

Boron Chemistry for Medical Applications

2020

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Boron compounds now have many applications in a number of fields, including Medicinal Chemistry. Although the uses of boron compounds in pharmacological science have been recognized several decades ago, surprisingly few are found in pharmaceutical drugs. The boron-containing compounds epitomize a new class for medicinal chemists to use in their drug designs. Carboranes are a class of organometallic compounds containing carbon (C), boron (B), and hydrogen (H) and are the most widely studied boron compounds in medicinal chemistry. Additionally, other boron-based compounds are of great interest, such as dodecaborate anions, metallacarboranes and metallaboranes. The boron neutron capture therapy (BNCT) has been utilized for cancer treatment from last decade, where chemotherapy and radiation have their own shortcomings. However, the improvement in the already existing (BPA and/or BSH) localized delivery agents or new tumor-targeted compounds are required before realizing the full clinical potential of BNCT. The work outlined in this short review addresses the advancements in boron containing compounds. Here, we have focused on the possible clinical implications of the new and improved boron-based biologically active compounds for BNCT that are reported to have in vivo and/or in vitro efficacy.

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Section: Boron Clusters For Medical Applicationsmentioning

confidence: 99%

Boron Chemistry for Medical Applications

2020

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“…[88]. Panels reprinted with permission from [89]. Copyright (2018) by the American Physical Society.…”

Section: Radiative Cooling and Abundancesmentioning

confidence: 99%

“…At present, five metal or semi-metal cluster systems have been investigated with the delayed extraction/metastable fraction technique described previously, viz. Nb + N [111], Si + N [67], B + N [89], Au + N [43] and Pt + N [65], all of them using the same experimental setup and similar experimental conditions. This allows a direct comparison of the emission rates for the different clusters.…”

Section: Radiative Cooling Rates Of Metal and Semi-metal Clustersmentioning

confidence: 99%

Radiative cooling of size-selected gas phase clusters

Ferrari

Janssens

Lievens

et al. 2019

International Reviews in Physical Chemistry

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Predicted almost forty years ago, the radiation from thermally populated excited electronic states has recently been recognized as an important cooling mechanism in free molecules and clusters. It has presently been observed from both inorganic clusters and carbon-based molecules in molecular beams and ion storage devices. Experiments have demonstrated that many of these systems radiate at rates approaching microsecond time scales, and often with a distinct dependence on the precise number of atoms in the system. The radiation acts as a strongly stabilizing factor against both unimolecular decay and thermal electron emission. In astrophysical context, radiative cooling provides a mechanism to dissipate internal energy in star-forming processes, and stabilizes molecules selectively in the circumstellar medium. The consequences of an active radiative cooling channel for nanoparticle production will likewise favor special sizes in nonequilibrium formation processes. In this review, the radiative cooling of clusters is presented and illustrated with examples of experiments performed on small carbon, metal, and semiconductor clusters, and on PAH molecules. The experimental and theoretical techniques used are discussed, together with the consequences of radiative cooling on size-to-size stability patterns of clusters.

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“…It is important to mention, the emission of radiation as a competing cooling channel has to be considered in studying small cationic boron clusters’ stabilities. According to Ferrari et al, this improving agreement between experiment and theory [ 49 ]. In this study, we consider that temperature and entropy are critical for elucidating low-energy structures and highlight the importance of understanding the thermal and entropic effects in the Be 6 B 11 − fluxional cluster.…”

Section: Introductionmentioning

confidence: 98%

Exploration of Free Energy Surface and Thermal Effects on Relative Population and Infrared Spectrum of the Be6B11− Fluxional Cluster

et al. 2020

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The starting point to understanding cluster properties is the putative global minimum and all the nearby local energy minima; however, locating them is computationally expensive and difficult. The relative populations and spectroscopic properties that are a function of temperature can be approximately computed by employing statistical thermodynamics. Here, we investigate entropy-driven isomers distribution on Be6B11− clusters and the effect of temperature on their infrared spectroscopy and relative populations. We identify the vibration modes possessed by the cluster that significantly contribute to the zero-point energy. A couple of steps are considered for computing the temperature-dependent relative population: First, using a genetic algorithm coupled to density functional theory, we performed an extensive and systematic exploration of the potential/free energy surface of Be6B11− clusters to locate the putative global minimum and elucidate the low-energy structures. Second, the relative populations’ temperature effects are determined by considering the thermodynamic properties and Boltzmann factors. The temperature-dependent relative populations show that the entropies and temperature are essential for determining the global minimum. We compute the temperature-dependent total infrared spectra employing the Boltzmann factor weighted sums of each isomer’s infrared spectrum and find that at finite temperature, the total infrared spectrum is composed of an admixture of infrared spectra that corresponds to the spectra of the lowest-energy structure and its isomers located at higher energies. The methodology and results describe the thermal effects in the relative population and the infrared spectra.

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Effect of radiative cooling on the size-dependent stability of small boron clusters

Cited by 15 publications

References 28 publications

Boron Chemistry for Medical Applications

Boron Chemistry for Medical Applications

Radiative cooling of size-selected gas phase clusters

Exploration of Free Energy Surface and Thermal Effects on Relative Population and Infrared Spectrum of the Be6B11− Fluxional Cluster

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