Related Experiment Video
Updated: Feb 16, 2026
08:22
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
7.4K
Absolute vibrational excitation cross sections for 1-18 eV electron scattering from condensed dimethyl phosphate
V Lemelin1, A D Bass1, J R Wagner1
1Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et Sciences des Radiations, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada.
The Journal of Chemical Physics
|December 24, 2017
Summary
This study measured electron-induced vibrational excitation in condensed dimethyl phosphate (DMP). Observed structures in cross sections indicate the formation of shape resonances, providing insights into electron scattering dynamics.
Area of Science:
- Physics
- Chemistry
- Materials Science
Background:
- Understanding electron interactions with condensed matter is crucial for various scientific fields.
- Dimethyl phosphate (DMP) is a molecule of interest due to its potential biological and chemical relevance.
- Previous studies have investigated electron scattering on gaseous DMP, but condensed-phase data is less explored.
Purpose of the Study:
- To measure absolute cross sections for vibrational excitation in condensed DMP using electron impact.
- To identify and characterize energy-dependent structures in the electron scattering spectra.
- To correlate observed structures with theoretical models and experimental data from gas-phase studies.
Main Methods:
- Utilized a high-resolution electron energy loss (EEL) spectrometer.
- Condensed DMP films on a multilayer Argon film at approximately 20 K under ultra-high vacuum conditions (∼1 × 10-11 Torr).
- Analyzed EEL spectra to extract absolute cross sections (CSs) for electron-induced vibrational excitation.
Main Results:
- Measured absolute CSs for electron scattering on condensed DMP over an energy range of 1-18 eV.
- Identified distinct structures in the energy dependence of CSs at approximately 2, 4, 7, and 12 eV.
- These structures align with findings from gas-phase experiments and theoretical calculations for DMP and related molecules.
Conclusions:
- The observed spectral structures are attributed to the formation of shape resonances during electron scattering.
- This study provides valuable experimental data on electron-molecule interactions in the condensed phase.
- The findings enhance the understanding of electron scattering dynamics in organophosphates.
Related Concept Videos
01:20¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
1.7K
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
1.7K
01:14Molecular Spectroscopy: Absorption and Emission
4.7K
Molecules possess discrete energy levels called quantum states. Unlike atoms, which have simpler energy levels, molecules possess additional rotational and vibrational energy levels. Each energy level is separated by an energy gap, with the gaps between adjacent electronic, vibrational, and rotational levels varying significantly. The three types of energy levels in a diatomic molecule are shown in Figure 1.
4.7K
01:27π Electron Effects on Chemical Shift: Overview
1.7K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.7K
01:16UV–Vis Spectroscopy: Molecular Electronic Transitions
3.0K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
3.0K
01:13¹H NMR: Complex Splitting
1.9K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
1.9K
01:07Proton (¹H) NMR: Chemical Shift
3.6K
Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
Absorption signals of all the protium nuclei...
Absorption signals of all the protium nuclei...
3.6K