“photoelectron spectroscopy”的概念、定义、翻译、参考文献-科学参考

photoelectron spectroscopy

Physics

A technique for determining the ionization potentials of molecules. The sample is a gas or vapour irradiated with a narrow beam of ultraviolet radiation (usually from a helium source at 58.4 nm, 21.21 eV photon energy). The photoelectrons produced in accordance with Einstein’s equation are passed through a slit into a vacuum region, where they are deflected by magnetic or electrostatic fields to give an energy spectrum. The photoelectron spectrum obtained has peaks corresponding to the ionization potentials of the molecule (and hence the orbital energies). The technique also gives information on the vibrational energy levels of the ions formed. ESCA (electron spectroscopy for chemical analysis) is a similar analytical technique in which a beam of X-rays is used. In this case, the electrons ejected are from the inner shells of the atoms. Peaks in the electron spectrum for a particular element show characteristic chemical shifts, which depend on the presence of other atoms in the molecule.

Chemistry

A technique for determining the ionization potentials of molecules. In ultraviolet photoelectron spectroscopy (UPS) the sample is a gas or vapour irradiated with a narrow beam of ultraviolet radiation (usually from a helium source at 58.4 nm, 21.21 eV photon energy). The photoelectrons produced in accordance with the Einstein equation are passed through a slit into a vacuum region, where they are deflected by magnetic or electrostatic fields to give an energy spectrum. The photoelectron spectrum obtained has peaks corresponding to the ionization potentials of the molecule (and hence the orbital energies). The technique also gives information on the vibrational energy levels of the ions formed. X-ray photoelectron spectroscopy (XPS), also known as ESCA (electron spectroscopy for chemical analysis), is a similar analytical technique in which a beam of X-rays is used. In this case, the electrons ejected are from the inner shells of the atoms. Peaks in the electron spectrum for a particular element show characteristic chemical shifts, which depend on the presence of other atoms in the molecule. See also Koopmans’ theorem.

Electronics and Electrical Engineering

A method of analysis of the composition of a semiconductor by detecting photoelectrons generated by photons impinging on the surface of the material (see photoelectric effect). The method is nondestructive and only photoelectrons generated at or very near to the surface are detected. The photoelectrons have an energy typical of the parent atom, but also characterized by neighbouring atoms: chemical bonding between the parent atom and its neighbours causes perturbations of the energies detected.
X-ray photoelectron spectroscopy (XPS) uses photons in the X-ray range of energy and ultraviolet photoelectron spectroscopy (UPS) uses photons in the ultraviolet energy range. This technique contrasts with Auger electron spectroscopy in that the electrons result from transitions between the outer atomic orbitals (XPS) or the valence and conduction bands (UPS) as opposed to electrons in the inner orbitals (Auger ES). XPS yields sharper more easily identifiable energy peaks than UPS but since focusing is not easy the lateral resolution is poor.

单词	photoelectron spectroscopy
释义	photoelectron spectroscopy Physics A technique for determining the ionization potentials of molecules. The sample is a gas or vapour irradiated with a narrow beam of ultraviolet radiation (usually from a helium source at 58.4 nm, 21.21 eV photon energy). The photoelectrons produced in accordance with Einstein’s equation are passed through a slit into a vacuum region, where they are deflected by magnetic or electrostatic fields to give an energy spectrum. The photoelectron spectrum obtained has peaks corresponding to the ionization potentials of the molecule (and hence the orbital energies). The technique also gives information on the vibrational energy levels of the ions formed. ESCA (electron spectroscopy for chemical analysis) is a similar analytical technique in which a beam of X-rays is used. In this case, the electrons ejected are from the inner shells of the atoms. Peaks in the electron spectrum for a particular element show characteristic chemical shifts, which depend on the presence of other atoms in the molecule. Chemistry A technique for determining the ionization potentials of molecules. In ultraviolet photoelectron spectroscopy (UPS) the sample is a gas or vapour irradiated with a narrow beam of ultraviolet radiation (usually from a helium source at 58.4 nm, 21.21 eV photon energy). The photoelectrons produced in accordance with the Einstein equation are passed through a slit into a vacuum region, where they are deflected by magnetic or electrostatic fields to give an energy spectrum. The photoelectron spectrum obtained has peaks corresponding to the ionization potentials of the molecule (and hence the orbital energies). The technique also gives information on the vibrational energy levels of the ions formed. X-ray photoelectron spectroscopy (XPS), also known as ESCA (electron spectroscopy for chemical analysis), is a similar analytical technique in which a beam of X-rays is used. In this case, the electrons ejected are from the inner shells of the atoms. Peaks in the electron spectrum for a particular element show characteristic chemical shifts, which depend on the presence of other atoms in the molecule. See also Koopmans’ theorem. Electronics and Electrical Engineering A method of analysis of the composition of a semiconductor by detecting photoelectrons generated by photons impinging on the surface of the material (see photoelectric effect). The method is nondestructive and only photoelectrons generated at or very near to the surface are detected. The photoelectrons have an energy typical of the parent atom, but also characterized by neighbouring atoms: chemical bonding between the parent atom and its neighbours causes perturbations of the energies detected. X-ray photoelectron spectroscopy (XPS) uses photons in the X-ray range of energy and ultraviolet photoelectron spectroscopy (UPS) uses photons in the ultraviolet energy range. This technique contrasts with Auger electron spectroscopy in that the electrons result from transitions between the outer atomic orbitals (XPS) or the valence and conduction bands (UPS) as opposed to electrons in the inner orbitals (Auger ES). XPS yields sharper more easily identifiable energy peaks than UPS but since focusing is not easy the lateral resolution is poor.
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