Vibrational Fingerprints of Low-Lying Pt_nP_2n (n = 1–5) Cluster Structures from Global Optimization Based on Density Functional Theory Potential Energy Surfaces

Abstract

Vibrational fingerprints of small Pt n P 2n (n=1-5) clusters were computed from their low-lying structures located from a global exploration of their DFT potential energy surfaces with the GSAM code. Five DFT methods were assessed from the CCSD(T) wavenumbers of PtP 2 species and CCSD relative energies of Pt 2 P 4 structures. The eight first Pt n P 2n isomers found are reported. The vibrational computations reveal (i) the absence of clear signatures made by overtone or combination bands due to very weak mechanical and electrical anharmonicities (ii) some significant and recurrent vibrational fingerprints in correlation with the different PP bonding situations in the Pt n P 2n structures.

Improving Vibrational Mode Interpretation Using Bayesian Regression

“…Indeed, considering only the four largest local a The atomic numbering follows the scheme depicted in Figure 4. contributions would cover 50% of the atomic motions, and can be easily interpreted as a rising of the molecule's extremes (atoms C 1 , C 2 , C 12 , and C 13 ) relative to the original plane of the molecule. On the other hand, the movement along the 48.8 cm −1 mode of helicene is described by VMARD using 13 internal coordinates.…”

“…The results displayed in Table 2 prompted the question of whether the use of additional (user-defined) internal coordinates would help describing these poorly localized modes. In the case of anthracene, two hypothesis were tested: in one case, we manually added the two torsions (τC (2) C ( 10) C ( 7) C (12) and τC (1) C ( 7) C ( 10) C ( 13) ), while in the second experiment two angle bendings were added (δC (2) C ( 10) C (13) and δC (1) C ( 7) C ( 12) ). The first case was mildly successful, with τC (1) C ( 7) C ( 10) C ( 13) achieving a weight of 15% in describing the atomic motions associated with the mode depicted in Figure 4a, with a corresponding decrease in the weights of the other internal coordinates listed in Table 2.…”

“…Alongside with NMR spectroscopy, analysis of vibrational spectra is one of the most important techniques for understanding the structure and behavior of matter at the nano- and subnanoscales. Indeed, vibrational spectroscopic techniques, such as Fourier transform infrared (FTIR) and Raman spectroscopy permeate the chemical literature, providing valuable insights for the elucidation of molecular structures, , the organization of molecular clusters, − the role on interion interactions in ionic liquids, , as well as insights on the organization of novel nanostructured materials. − In latter years, theoretical predictions became essential tools, aiding in the interpretation of IR and Raman spectra . In addition to the aforementioned applications, theoretical predictions are a valuable aid in identifying the product of chemical reactions out of several possible outcomes, − and also allow the calculation of the thermodynamic and kinetic parameters of these reactions. − …”

Characterization of the Effects of Ligands on Bonding and σ-Aromaticity of Small Pt Nanoclusters

“…Computational studies have examined the molecular and electronic structures of bare Pt nanoclusters. − Another study examined the molecular structure and vibrational features of platinum–phosphorus mixed clusters, Pt n P 2 n ( n = 1–5), using density functional theory (DFT) . Meanwhile, Huang and Lee used a cluster model approach to simulate the adsorption of CO on a Pt surface .…”

“… 13 − 15 Another study examined the molecular structure and vibrational features of platinum–phosphorus mixed clusters, Pt n P 2 n ( n = 1–5), using density functional theory (DFT). 16 Meanwhile, Huang and Lee used a cluster model approach to simulate the adsorption of CO on a Pt surface. 13 The study concluded that the size of the cluster impacts the adsorption of CO.…”