Influence of Guest−Host Interactions on the Structural, Energetic, and Mössbauer Spectroscopy Properties of Iron(II)tris(2,2′-bipyridine) in the Low-Spin and High-Spin States: A Density-Functional Theory Study of the Zeolite-Y Embedded Complex

Abstract

Density functional theory is applied within a supramolecular approach to the study of the guest-host interactions in [Fe(bpy) Fe quadrupole splitting, whose calculated values are in very good agreement with avalaible experimental data. The decomposition of the guest-host interaction energy into its electrostatic, Pauli and orbital contributions shows that the bonding between the complex and the supercage is more electrostatic than covalent. The ability of modern functionals to accurately describe the interactions explains the remarkable consistency of the results obtained with the various functionals. In particular, although the functionals perform very differently for the determination of the high-spin/low-spin energy difference ∆E HL el in [Fe(bpy)

Molecular Spin Crossover Materials: Review of the Lattice Dynamical Properties

“…Since the pioneering works of Paulsen, throughout the past 20 years, DFT calculations proved to be very useful tools to investigate various properties of SCO systems. These include the calculation of i) molecular geometries, ii) charge and spin densities, iii) potential energy curves, excited state energies, and electronic spectra, iv) surface adsorption and charge transport properties, v) normal modes of vibration and the corresponding vibrational spectra (IR, Raman, NIS), as well as vi) different derived thermodynamical properties, such as the vibrational contributions to the enthalpy and entropy . In particular, calculation of spin state energetics (adiabatic energy differences) received much attention with the aim to predict the spin transition temperatures, but this remains a challenging problem .…”

On the role of the metal‐to‐ligand charge transfer states in the light‐induced spin crossover in FeII (bpy)3

“…DFT calculations have also been used to obtain estimates of the energy difference between the initial nonmagnetic state ( 1 A 1 ) and the final highspin state ( 5 T 2 ) [31][32][33][34][35]. More recently, intents are also made to address excited states and environmental effects [36][37][38][39]. However, the application of wave function-based methods is also emerging.…”

Electron smearing in DFT calculations: A case study of doxorubicin interaction with single‐walled carbon nanotubes

“…The smallest value used, to the best of our knowledge, was 0.00004 Ha [63] (1 Ha ¼ 27.2114 eV), other examples being 0.0005 [21,22,25,55], 0.001 [6,15,30,48], 0.002 [7, 19, 31, 35-37, 53, 62, 66, 67], 0.003 [3,29], 0.004 [43-45, 52, 54, 65], 0.005 [4, 5, 8-14, 20, 23, 24, 27, 28, 32, 33, 39, 42, 47, 49, 57-59, 61, 64], 0.007 [34,38,41,51], 0.01 [16,40], 0.02 [17,18,60] and finally 0.035 Ha [40]. Attempts to justify the choice of smearing value are extremely rare [40]; instead, it seems to be rather arbitrary, with occasional comments regarding, for example, 0.001 Ha as ''a small smearing'' [15], 0.005 Ha as ''an appropriate value'' [4], etc.…”

“…The former systems comprise transition metal clusters (including nanoclusters) without [1,[3][4][5][6][7][8] and with adsorbed/chemisorbed species [9][10][11][12][13][14], metal oxides [15], and chemisorption on their surfaces [16][17][18][19], carbides [20], sulfides [21,22], and their adsorption properties [23][24][25], relatively simple transition metal coordination complexes [2], organometallic compounds [26][27][28], as well as large supramolecular species [29,30]. Also, SCF convergence can be facilitated by applying Fermi smearing when calculating light-element cluster models composed of H, C, N, and O only: a few examples are defects in nanodiamond [31], cold-plasma methanol conversion [32], and amino acid adsorption on short single-walled carbon nanotubes (SWNTs) [33].…”

“…There is a number of molecular modeling packages, in which electron smearing option is available: the reports cited above used the Amsterdam Density Functional (ADF) software [1,29]; Cerius2 [3], DMol 3 [4-28, 30-33, 35-37, 39, 42, 46, 47, 49, 53, 55, 58, 59, 61, 64, 66, 67] and Cambridge Sequential Total Energy Package (CASTEP) [45,60] modules (from Accelrys Inc., formerly Molecular Simulations Inc.); the Vienna Ab initio Simulation Package (VASP) [34, 38, 41, 43, 44, 50-52, 54, 65] CRYSTAL03 periodic code [40]; the plane-wave self-consistent field (PWscf) code [48,56]; the Quantum ESPRESSO package [57,62]; and the plane wave, pseudopotential code Dacapo [63].…”