Photoionization efficiency spectroscopy and density functional theory investigations of RhHo2On (n=–2) clusters

Abstract

The experimental and theoretical adiabatic ionization energies ͑IEs͒ of the rhodium-holmium bimetallic clusters RhHo 2 O n ͑n =0-2͒ have been determined using photoionization efficiency spectroscopy and density functional theory ͑DFT͒ calculations. Both sets of data show the IE of RhHo 2 O to be significantly lower than the values for RhHo 2 and RhHo 2 O 2 , which are found to be similar. This indicates that there are significant changes in electronic properties upon sequential addition of oxygen atoms to RhHo 2 . The DFT investigations show that the lowest energy neutral structures are a C 2v triangle for RhHo 2 , a C 2v planar structure for RhHo 2 O where the O atom is doubly bridged to the Ho-Ho bond, and a C 2v nonplanar structure for RhHo 2 O 2 , where the O 2 is dissociative and each O atom is doubly bridged to the Ho-Ho bond in the cluster above and below the RhHo 2 trimer plane. Good correlation between the experimental and computational IE data imply that the lowest energy neutral structures calculated are the most likely isomers ionized in the molecular beam. In particular, the theoretical adiabatic IE for the dissociative RhHo 2 O 2 structure is found to compare better with the experimentally determined value than the corresponding lowest energy O 2 associative structure.

Using Photoionization Efficiency Spectroscopy and Density Functional Theory to Investigate Charge Transfer Interactions in AuCe3On Clusters

“…The IEs of the bare metal clusters, Ce 3 and AuCe 3 , are corrected to match their respective experimental IE values and the same correction is then applied to the each of the cluster oxides. This method of correction has been employed previously − and error bars of ±0.2 eV are assigned to all calculated IE values to account for any inherent uncertainties in the DFT calculated energies.…”

“…This cools the internal vibrational temperatures of all clusters to ca. 300 K, as reported previously. − For stable metastable states, we assume that significant population can exist in low-lying energy states within each multiplicity, as has been observed in metal-containing molecules and clusters. , …”

“…The experimental apparatus has been discussed at length in both our previous work and elsewhere. − Briefly, gold and cerium rods are ablated independently with two separate Nd:YAG lasers. Surface oxygen atoms present on the cerium rod due to oxidation are also ablated in this process, which facilitates the production of metal oxide clusters.…”

Investigating Pt Atom Addition to Gas Phase Ce2On Clusters Using Photoionization Efficiency Spectroscopy and Density Functional Theory

“…The detailed experimental setup and methodology have been reported previously . Briefly, helium carrier gas (99.996%, 60 psi) is pulsed into a 3 mm wide ablation channel, passing two rotating and translating metal rods of cerium (DXL, 99.9%) and isotopically enriched platinum (NIDC 99.6% Pt; >97% Pt-195).…”

“…The detailed experimental setup and methodology have been reported previously. 39 Briefly, helium carrier gas (99.996%, 60 psi) is pulsed into a 3 mm wide ablation channel, passing two rotating and translating metal rods of cerium (DXL, 99.9%) and isotopically enriched platinum (NIDC 99.6% Pt; >97% Pt-195). The rods are ablated with the second harmonic output of two separate Nd:YAG lasers, the products of which are entrained in the carrier gas pulse which then flows through a 20 mm long, 2 mm wide condensation tube, enabling cluster growth from the ablated metal gases.…”