Mn2 dimers encapsulated in silicon cages: a complex challenge to MC-SCF theory

<div>MC-SCF wavefunctions for three endohedral Mn/Si clusters, Mn<sub>2</sub>Si<sub>10</sub>, Mn<sub>2</sub>Si<sub>12</sub>, and [Mn<sub>2</sub>Si<sub>13</sub>]<sup>+</sup>, show evidence for strong static corr...

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Bibliographic Details
Main Authors: Khanna, V, McGrady, JE
Format: Journal article
Language:English
Published: MDPI 2022
Description
Summary:<div>MC-SCF wavefunctions for three endohedral Mn/Si clusters, Mn<sub>2</sub>Si<sub>10</sub>, Mn<sub>2</sub>Si<sub>12</sub>, and [Mn<sub>2</sub>Si<sub>13</sub>]<sup>+</sup>, show evidence for strong static correlation, both in the Mn-Si bonds (&lsquo;in&ndash;out correlation&rsquo;) and between the two Mn centers (&lsquo;up&ndash;down correlation&rsquo;). We use both Restricted and Generalized Active Spaces (RAS and GAS) to place constraints on the configurations included in the trial wavefunction, showing that, particularly in the high-symmetry cases, the GAS approach captures more of the static correlation. The important correlating pairs are similar across the series, indicating that the electronic structure of the endohedral Mn<sub>2</sub>&nbsp;unit is, to a first approximation, independent of the size of the silicon cage in which it is embedded.</div>