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Register a new userRelative abundances and enantiomerization energy of the chiral Cu$_{13}$ cluster at finite temperature
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This study reports the lowest energy structure of bare Cu$_{13}$ nanoclusters as a pair of enantiomers for temperatures ranging from 20 to 1200 K. Moreover, we compute the enantiomerization energy for the interconversion from $mathcal{M}$ to $mathcal{P}$ structures in the chiral putative global minimum for temperatures ranging from 20 to 1300 K. Additionally, employing statistical thermodynamics and nanothermodynamics, we compute the Boltzmann Probability for each particular isomer as a function of temperature. To achieve that, we explore the free energy surface of the Cu$_{13}$ cluster, employing a genetic algorithm coupled with density functional theory and statistical thermodynamics. Moreover, we discuss the energetic ordering of structures computed at the DFT level and compared to high level DLPNO-CCSD(T1) reference energies, and we present chemical bonding analysis using the AdNDP method in the chiral putative global minimum. Based on the computed relative abundances, our results show that the chiral putative global minimum strongly dominates for temperatures ranging from 20 to 1100 K.
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The lowest-energy structure, distribution of isomers, and their molecular properties depend significantly on the geometry and temperature. The total energy computations under DFT methodology are typically carried out at zero temperature; thereby, entropic contributions to total energy are neglected, even though functional materials work at finite temperature. In the present study, the probability of occurrence of one particular Be$_4$B$_8$ isomer at temperature T is estimated within the framework of quantum statistical mechanics and nanothermodynamics. To locate a list of all possible low-energy chiral and achiral structures, an exhaustive and efficient exploration of the potential/free energy surface is done by employing a multilevel multistep global genetic algorithm search coupled to DFT. Moreover, we discuss the energetic ordering of structures computed at the DFT level against single-point energy calculations at the CCSD(T) level of theory. The computed VCD/IR spectrum of each isomer is multiplied by their corresponding Boltzmann weight at temperature T; then, they are summed together to produce a final Boltzmann weighted spectrum. Additionally, we present chemical bonding analysis using the Adaptive Natural Density Partitioning method in the chiral putative global minimum. The transition state structures and the enantiomer-enantiomer and enantiomer-achiral activation energies as a function of temperature, evidence that a change from an endergonic to an exergonic type of reaction occurs at a temperature of 739 K.
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