Dynamic behavior of valence-shell excitations of atomic neon studied by high-resolution inelastic x-ray scattering

Abstract

The high-resolution inelastic x-ray scattering has been applied to study the excitation mechanism of atomic neon. The different electric multipolar transitions of neon, i.e., the electric monopolar, dipolar, and quadrupolar ones, were clearly resolved, and their squared form factors were determined. It is found that for the monopolar and quadrupolar transitions the present inelastic x-ray scattering results are in agreement with the ones measured by high-energy electron scattering, while for the dipolar transition large discrepancies between the results measured by these two methods were observed. Such phenomena are well elucidated with the aid of the second-order Born approximation: Born amplitude of a transition near zero momentum transfer is the key factor which determines the behavior of the intramolecular multiple scattering in the high-energy electron scattering. It is revealed that the intramolecular multiple scattering in high-energy electron scattering must be considered for the dipole-allowed transition, while it is negligible for the dipole-forbidden ones.

Determination of the electronic structure of atoms and molecules in the ground state: Measurement of molecular hydrogen by high-resolution x-ray scattering

“…Furthermore, the ionization continuum also contributes to the elastic scattering in these experiments due to the same reason. So these previous elastic differential cross sections definitely have contributions from the inelastic scattering, which have been observed recently by inelastic x-ray-scattering experiments [8][9][10][11]. Because of the lack of experimental data, only Bentley et al [12,13] have calculated the elastic squared form factor of molecular hydrogen using ground wave functions prepared by different theoretical methods [14].…”

“…With the dramatic development of third-generation synchrotron radiation and the crystal spectrometer, the brightness and the energy resolution of the x-ray-scattering technique have been greatly improved, which provides the possibility for high-precision measurements of the elastic differential cross section of x-ray scattering by atoms and molecules. Recently, the dynamic parameters of the valence shell excitations of some atoms and molecules have been measured by the x-ray-scattering technique with high-energy resolution in our group [8][9][10][11] and with moderateenergy resolution in Seidler's group [15,16], and some interesting excitation mechanisms have been revealed. In this Brief Report, we extend this experimental technique to study the elastic scattering of the x ray by a free molecule, and pure electronic structure information about the ground state is determined.…”

“…The experimental setup used in this work is shown in Fig. 1 and has been described in our previous works [8][9][10][11]. Briefly, a Si(333) monochromator was used to achieve a high-energy resolution of 70 meV.…”

Ab initio calculation of inelastic scattering

“…These have been studied before, theoretically 46,59 and experimentally using both EELS 60 and IXS. 10 The IXS measurements by Zhu et al…”

A high resolution and large solid angle x-ray Raman spectroscopy end-station at the Stanford Synchrotron Radiation Lightsource

“…Further on, the high energy resolution of the end station (∼ 270 meV at low-q) could also render the present end-station as a powerful tool to reveal new insights related to low-energy non-dipole transitions in atoms and molecular systems through q-dependent studies within the low-q regime. [50][51][52][53][54][55][56][57][58] Moreover, XRS from semicore levels of heavy elements studied with the present instrument will give improved resolution of the overlapping multiplet featuresan important improvement for broader application of XRS to f-electron systems. [59][60][61][62] The continuous progress with the x-ray optics as well as the availability of modern undulator radiation beamlines, such as the anticipated new undulator beamline at SSRL dedicated to high resolution x-ray spectroscopy, will further boost this technique to a wide range of applications.…”