[Paper Review] Revisiting the Global Minimum Structure of the Pt5V Cluster

Peter L. Rodríguez‐Kessler|arXiv (Cornell University)|Aug 7, 2024

Nanocluster Synthesis and ApplicationsMaterials Science3 citations

TL;DR

This study investigates the global minimum structure of Pt5V clusters using density functional theory (DFT) with multiple functionals (PBE, PBE0, B3PW91, PBEh-3c, M06-L, TPSS) and the SCG method. The key finding is that two distinct isomers—capped trapezoid (5M1.1, quartet state) and pentagonal pyramid (5M1.2, doublet state)—compete for the global minimum depending on the functional used, highlighting functional-dependent stability in Pt-based nanoclusters.

ABSTRACT

In this work, the most stable structures of Pt5V clusters are investigated using the successive growth algorithm (SCG) in conjunction with density functional theory (DFT) calculations. The resulting structures are evaluated by various functionals, including GGA (PBE), meta-GGA (TPSS) and hybrid (B3PW91, PBE0, PBEh-3c, M06-L), in conjunction with the Def2TZVP basis set. The results based on these functionals show that two different structures compete for the global minimum. The structural and electronic properties of the two most stable structures are discussed.

Motivation & Objective

• To resolve the global minimum structure of Pt5V clusters, which remains debated due to functional dependency in DFT calculations.
• To evaluate the stability and electronic properties of Pt5V isomers using a range of DFT functionals and basis sets.
• To provide vibrational and electronic fingerprints (e.g., IR spectra, ionization energy) for experimental validation.
• To assess the role of spin multiplicity and coordination in determining structural preference.
• To support future design of cost-effective, high-activity Pt-based nanocatalysts through accurate cluster structure prediction.

Proposed method

• Employed the successive growth algorithm (SCG) for systematic exploration of Pt5V cluster isomers.
• Conducted DFT calculations using multiple exchange-correlation functionals: GGA (PBE), meta-GGA (TPSS), and hybrid (B3PW91, PBE0, PBEh-3c, M06-L).
• Used the Def2TZVP basis set and Grimme's D3(BJ) dispersion correction to account for van der Waals interactions.
• Performed geometry optimizations with BFGS algorithm and tight SCF convergence (10−8 au).
• Calculated vibrational frequencies (IR spectra), ionization energy (IP), electron affinity (EA), and chemical hardness (η) for structural validation.
• Evaluated effective coordination number (ECN) and average bond distance (dav) to analyze structural trends.

Experimental results

Research questions

• RQ1 Which Pt5V cluster isomer is the global minimum, and does this depend on the choice of DFT functional?
• RQ2 How do spin multiplicity and coordination number influence the relative stability of Pt5V isomers?
• RQ3 What are the characteristic vibrational frequencies that can serve as experimental fingerprints for distinguishing the most stable isomers?
• RQ4 How do ionization energy and electron affinity vary across different Pt5V isomers, and what do they reveal about electronic stability?
• RQ5 To what extent do structural and electronic properties of Pt5V clusters exhibit functional dependency in DFT calculations?

Key findings

• The PBE, PBEh-3c, M06-L, and TPSS functionals favor the pentagonal pyramid (5M1.2) in the doublet state as the global minimum, with relative energy 0.00 eV.
• The PBE0 and B3PW91 functionals identify the capped trapezoid (5M1.1) in the quartet state as the global minimum, also with 0.00 eV relative energy.
• The IR spectrum of 5M1.1 shows characteristic peaks at 304.36 cm−1 and 381.58 cm−1, while 5M1.2 exhibits peaks at 301.23 cm−1 and 335.16 cm−1.
• Ionization energies for all isomers range from 7.05 to 7.58 eV, with electron affinities between 2.16 and 2.57 eV, indicating minimal variation across structures.
• Effective coordination number (ECN) increases with spin multiplicity, indicating a structural and spin-dependent coordination trend.
• Both 5M1.1 and 5M1.2 exhibit C1 symmetry and a 4A electronic state, with only minor differences in chemical hardness and chemical potential.