Related Experiment Video
Updated: Jun 17, 2026
08:04
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Superatom spectroscopy and the electronic state correlation between elements and isoelectronic molecular counterparts
Samuel J Peppernick1, K D Dasitha Gunaratne, A W Castleman
1Department of Materials Science and Engineering, 104 Chemistry Research Building, Pennsylvania State University, University Park, PA 16802, USA.
Summary
This study uses photoelectron spectroscopy to compare noble metal anions (Ni-, Pd-, Pt-) with isoelectronic diatomic molecules (TiO-, ZrO-, WC-). Results reveal a "superatom" electronic structure in molecules, mimicking atomic behavior.
Area of Science:
- Atomic and Molecular Physics
- Spectroscopy
- Quantum Chemistry
Background:
- Photoelectron spectroscopy is a powerful tool for probing the electronic structure of atoms and molecules.
- Understanding the electronic similarities between atomic ions and molecular ions can provide insights into chemical bonding and reactivity.
- The superatom concept describes how clusters of atoms can exhibit electronic properties analogous to individual atoms.
Purpose of the Study:
- To investigate the electronic structure of group 10 noble metal anions (Ni-, Pd-, Pt-) using photoelectron imaging.
- To compare the spectroscopic properties of these anions with their isoelectronic early transition metal diatomic molecular counterparts (e.g., TiO-, ZrO-, WC-).
- To explore the validity of the superposition principle and the superatom concept in molecular systems.
Main Methods:
- Experimental photoelectron imaging spectroscopy was employed.
- Measurements were performed on Ni-, Pd-, and Pt- anions at a photon energy of 2.33 eV (532 nm).
- Comparison was made with photoelectron images of isoelectronic diatomic molecules (M-X-, where M = Ti, Zr, W and X = O or C).
Main Results:
- A superposition principle was observed, demonstrating a strong correlation between the electronic spectroscopy of the atomic ions and their isoelectronic molecular counterparts.
- The electronic structure of the studied diatomic molecules was found to mimic that of the isoelectronic atoms.
- The molecular ions TiO-, ZrO-, and WC- exhibit superatomic electronic structures.
Conclusions:
- The study provides experimental evidence for the superatom concept in heterogeneous diatomic molecules.
- The findings quantify the superatom concept by demonstrating analogous electronic structures between atomic ions and molecular ions.
- This work bridges the understanding of electronic properties across atomic and molecular systems.
More Related Videos
Related Concept Videos
01:23Atomic Spectroscopy: Absorption, Emission, and Fluorescence
Atomic spectroscopy is a vital tool in elemental analysis, both qualitatively and quantitatively. It can be broadly divided into optical spectroscopy, mass spectroscopy, and X-ray spectroscopy methods. The optical spectroscopic methods are atomic absorption spectroscopy (AAS), atomic emission spectroscopy (AES), and atomic fluorescence spectroscopy (AFS). The first step in all three methods is atomization, where the solid, liquid, or solution-phase samples are converted into gas-phase atoms and...
01:13Mass Spectrometry: Isotope Effect
Most elements exist in nature as a mixture of isotopes. The isotopes differ in weight due to their respective number of neutrons. The molecular weight of a molecule is different depending on the specific isotope of its elements involved. As a result, the mass spectrum of the molecule exhibits peaks from the same fragment at multiple positions. The positions of these mass signals depend on the mass differences between isotopes. Furthermore, the intensity of these signals is dependent on the...
01:20Atomic Emission Spectroscopy: Overview
Atomic emission spectroscopy (AES) is an analytical technique used to determine the elemental composition of a sample by analyzing the light emitted from excited atoms. In AES, atoms in a sample are excited to higher energy levels by thermal energy from high-temperature sources, such as plasma, arcs, or sparks. When these excited atoms return to lower energy states, they emit light at specific wavelengths characteristic of each element. The resulting atomic emission spectrum, which consists of...
02:28Electronic Structure of Atoms
An atom comprises protons and neutrons, which are contained inside the dense, central core called the nucleus, with electrons present around the nucleus. Taking into account the wave–particle duality of electrons and the uncertainty in position around the nucleus, quantum mechanics provides a more accurate model for the atomic structure. It describes atomic orbitals as the regions around the nucleus where electrons of discrete energy exist, characterized by four quantum numbers: n, l, ml, and...
01:27Atomic Absorption Spectroscopy: Overview
Atomic absorption spectroscopy (AAS) is a technique used to analyze elements by measuring electromagnetic radiation (EMR) absorbed by atoms, which causes them to transition to a higher-energy orbit. The most crucial step in AAS is atomization, where the analyte is converted into gas-phase atoms, typically through a flame or furnace. Some of these atoms become thermally excited in the flame, while most remain in the ground state.
When irradiated by EMR of a particular wavelength, these...
When irradiated by EMR of a particular wavelength, these...
01:25Atomic Absorption Spectroscopy: Atomization Methods
Atomic Absorption Spectroscopy (AAS) atomizes samples through flame atomization or electrothermal atomization. Flame atomization typically involves a nebulizer and spray chamber assembly to combine the sample with a fuel–oxidant mixture, creating a fine aerosol mist that enters a burner. Typically, the fuel and oxidant are combined in an approximately stoichiometric ratio. However, for atoms that are easily oxidized, a fuel-rich mixture may be more advantageous. Only about 5% of the aerosol...