High-resolution saturation spectroscopy of the H2n = 3 triplet states

Jozefowski, L.; Ottinger, Ch.; Rox, T.

doi:10.1016/0009-2614(92)85346-c

Cited by 14 publications

(8 citation statements)

References 12 publications

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“…The p-H 2 was converted from liquid normal-H 2 by an iron oxide and chromium oxide catalyst. The p-H 2 content obtained with this method was previously determined by Jozefowski et al [14] to be about 95%. Because of the large energy difference between the allowed rotational states of p-H 2 (DE͑ j 0 !…”

mentioning

confidence: 62%

Observation of Large Differences in the Diffraction of Normal- and Para-H2from LiF(001)

Bertino¹,

Glebov²,

Toennies³

et al. 1998

Phys. Rev. Lett.

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Large differences have been observed in the diffraction intensities of normal-hydrogen and pure para-hydrogen scattered from the surface of a LiF(001) single crystal. The observed differences are shown to result from a strong coupling between the quadrupole moment of H 2 and the surface electrostatic field, which, in a zeroth order approximation, is averaged out in the case of para-hydrogen. Analogous effects are expected in scattering of all homonuclear diatomic molecules from ionic solids.

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mentioning

confidence: 62%

Observation of Large Differences in the Diffraction of Normal- and Para-H2from LiF(001)

Bertino¹,

Glebov²,

Toennies³

et al. 1998

Phys. Rev. Lett.

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“…81 Para-H 2 was prepared from liquid hydrogen using an iron oxide/ chromium oxide catalyst. 82,83 Since rather high H 2 gas pressures of up to 10 Ϫ5 mbar in the target chamber were necessary and at the low surface temperatures impurities such as CO or water molecules adsorb irreversibly and accumulate on the surface, great care had to be taken in baking and purging the gas line, which between experiments was pumped out with a turbo-molecular-pump to considerably lower than 10 Ϫ3 mbar.…”

Section: Measurement Methodsmentioning

confidence: 99%

Helium atom scattering studies of the structure and vibrations ofH2physisorbed on MgO(001) single crystals

et al. 2003

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The surface structure and vibrations of normal-H 2 , para-H 2 , HD, and normal-D 2 films physisorbed on in situ cleaved single crystal MgO͑001͒ surfaces, have been investigated at surface temperatures 7-12 K using high-resolution helium atom scattering. The He-diffraction patterns agree with the sequence of c(2ϫ2)c(4ϫ2)-c(6ϫ2) structures previously determined by neutron scattering. For the H 2 monolayer three different adsorbate frequencies, two Einstein modes around 10 meV and a dispersive mode between 2 and 7 meV, are found. HD and D 2 show the expected isotopomer shifts. A second probably ordered H 2 layer is formed upon further adsorption and exhibits one dispersionless mode at 5 meV.

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“…The para-H 2 was prepared by conversion of normal-H 2 on an iron oxide and chromium oxide catalyst in a dewar of liquid H 2 . The para-H 2 content obtained with these methods was previously determined 24,25 to be considerably greater than 95%.…”

Section: A Previous Workmentioning

confidence: 99%

Calculation of inelastic helium atom scattering from H2/NaCl(001)

Bruch

Hansen

Traeger³

2011

The Journal of Chemical Physics

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The one-phonon inelastic low energy helium atom scattering theory is adapted to cases where the target monolayer is a p(1 × 1) commensurate square lattice. Experimental data for para-H(2)/NaCl(001) are re-analyzed and the relative intensities of energy loss peaks in the range 6 to 9 meV are determined. The case of the H(2)/NaCl(001) monolayer for 26 meV scattering energy is computationally challenging and difficult because it has a much more corrugated surface than those in the previous applications for triangular lattices. This requires a large number of coupled channels for convergence in the wave-packet-scattering calculation and a long series of Fourier amplitudes to represent the helium-target potential energy surface. A modified series is constructed in which a truncated Fourier expansion of the potential is constrained to give the exact value of the potential at some key points and which mimics the potential with fewer Fourier amplitudes. The shear horizontal phonon mode is again accessed by the helium scattering for small misalignment of the scattering plane relative to symmetry axes of the monolayer. For 1° misalignment, the calculated intensity of the longitudinal acoustic phonon mode frequently is higher than that of the shear horizontal phonon mode in contrast to what was found at scattering energies near 10 meV for triangular lattices of Ar, Kr, and Xe on Pt(111).

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High-resolution saturation spectroscopy of the H2n = 3 triplet states

Cited by 14 publications

References 12 publications

Observation of Large Differences in the Diffraction of Normal- and Para-H2from LiF(001)

Observation of Large Differences in the Diffraction of Normal- and Para-H2from LiF(001)

Helium atom scattering studies of the structure and vibrations ofH2physisorbed on MgO(001) single crystals

Calculation of inelastic helium atom scattering from H2/NaCl(001)

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