Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 1510.08928

Nanocluster ionization energies and work function of aluminum, and their temperature dependence

Avik Halder·Vitaly V. Kresin
View original source ↗Read source document ↗Export metadata ↓

Abstract

Ionization threshold energies of Al$_n$ (n=32-95) nanoclusters are determined by laser ionization of free neutral metal clusters thermalized to several temperatures in the range from 65 K to 230 K. The photoion yield curves of cold clusters follow a quadratic energy dependence above threshold, in agreement with the Fowler law of surface photoemission. Accurate data collection and analysis procedures make it possible to resolve very small (few parts in a thousand) temperature-induced shifts in the ionization energies. Extrapolation of the data to the bulk limit enables a determination of the thermal shift of the polycrystalline metal work function, found to be in excellent agreement with theoretical prediction based on the influence of thermal expansion. Small clusters display somewhat larger thermal shifts, reflecting their greater susceptibility to thermal expansion. Ionization studies of free size-resolved nanoclusters facilitate understanding of the interplay of surface, electronic, and lattice properties under contamination-free conditions.

Explore related subjects

physics.atm-cluscond-mat.mtrl-sciphysics.chem-ph

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Avik Halder, Vitaly V. Kresin. 2015-10-29. Nanocluster ionization energies and work function of aluminum, and their temperature dependence. https://doi.org/10.1063/1.4934761

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Hydrogen isotope mixing entropy in ammonia clusters

Measured evaporation branching ratios of partially deuterated isotopologues of protonated ammonia clusters (NH$_3$)$_N$ H$^+$ ($N \geq 8$) show ratios that depend only on the clusters' deuterium mole fraction. This demonstrates randomly distributed protium and deuterium in the molecules and can be used to determine free energy differences in the product cluster. The entropy thus determined is exclusively the deuterium-protium mixing entropy. The relative dissociation energies of the four isotopologues are determined and with the support of quantum chemistry calculations, their absolute values are estimated.

physics.atm-clus↗
arXiv2026

What is superatom?

The term "superatom" was introduced over three decades ago to describe clusters that emulate elemental atoms. The field has long been guided by the spherical jellium model, where magic numbers arise from shell closure of delocalized electrons. This Perspective argues that delocalization, not near-sphericity, is what makes a system atom-like. It shows that superatomic shell structure persists under arbitrary point-group symmetry, that superatomicity survives as a tunable quantum state across pressurized, ionized, and chemically precompressed systems, and that the symmetry rules governing superatoms are conditional, deeper than the jellium picture admits. The future of this field lies not in finding more magic numbers, but in exploiting superatomic states as artificial quantum systems at the atomic level.

physics.atm-clus↗
arXiv2026

Electron scattering from polar hydrides using relativistic optical potential method

We extend the relativistic spherical complex optical-potential method with group additivity developed in our recent work [S. Arya and B. Antony, \textit{RSC Adv.} \textbf{16}, 13548--13558 (2026)] to molecules with permanent dipole moments. The short-range electronic collision is described by a central Dirac partial-wave calculation, while the missing anisotropic long-range dipole interaction is restored through a rotationally resolved first-Born contribution. The rotational thresholds, state-to-state transition-dipole strengths, and thermal populations are obtained from the HITRAN2024 spectroscopic database and thermally reweighted at the adopted rotational temperature. Both excitation and superelastic de-excitation channels are included. Electron scattering from benchmark polar hydrides ($\rm H_2O$, $\rm H_2S$, $\rm NH_3$, and $\rm PH_3$) is investigated over the incident-energy range 0.1--10,000 eV. We report vibrationally elastic, differential, integral, and momentum-transfer cross sections, together with a total cross section that also contains electronically inelastic loss from the quasifree absorption potential. The calculations reproduce the broad experimental and recommended trends over a wide energy range. The largest deviations are confined mainly to the low-energy and resonance-sensitive regions. Overall, the agreement improves substantially from the tens-of-eV region upward. The method therefore retains the low computational cost and wide energy coverage of the optical-potential approach while adding the long-range rotational physics needed for polar molecules.

physics.atm-clus↗