Shape Resonances in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>K</mml:mi></mml:math>-Shell Photoionization of Diatomic Molecules

Spin-and angle-resolved photoelectron spectroscopy with elliptically polarized radiation has been used to fully characterize the dynamics of photoelectron emission from free Xe atoms in the 5p-autoionization and continuum region. An advantageous reaction geometry and its experimental realization at the storage ring BESSY are discussed. The three independent experimental parameters which characterize the angular dependence of the photoelectron spin-polarization vector are reported for the wavelength range from i00nm to 40nm. The results are compared with theoretical predictions based on RRPA-, RPAE-and semiempirical MQDT-calculations. The combination of existing data for the differential photoionization cross section with the spinpolarization parameters is used to completely decouple the photoionization channels: The transition matrix elements and their relative phases are determined separately for every single dissociation channel. The results are discussed in the context of the MQDT. Correlation effects and the influence of spin-orbit interaction on the continuum states most clearly show up when the Dill-Fano angular-momentum-transfer formalism is applied.

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“…An alternative approach is the angular-momentum-transfer formalism, first applied by Dill and Fano [115,[120][121][122][123][124][125] …”

Section: Discussion In the Context Of The Angular-momentum-transfer Cmentioning

confidence: 99%

Experimental characterization of the Xe 5p photoionization by angle- and spin-resolved photoelectron spectroscopy

Heckenkamp

Schäfers

Schönhense

et al. 1986

Z Phys D - Atoms, Molecules and Clusters

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“…While the cross sections for s-and p-electrons in atoms or small molecules are typically maximal directly at the ionization threshold, 32 there exists a centrifugal barrier for d and f electrons that causes the maximum ionization cross section to be at higher energies. 33,34 These so called shape resonances can also occur in smaller molecules if the continuum wavefunction of the outgoing electron has components with a high l value, e.g., for the Σ states in CO. 35,36 The highest lying resonance in CO can be found at photon energies of 32 eV for the B 2 Σ + state.…”

Section: A Photon Energy Dependence Of the Electron Spectramentioning

confidence: 99%

Ionization and photofragmentation of Ru3(CO)12 and Os3(CO)12

Schalk

Josefsson

Richter

et al. 2015

The Journal of Chemical Physics

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In this paper, we use a combination of photoelectron spectroscopy, mass spectrometry, and density functional theory calculations to get a detailed understanding of valence single and double ionization and the subsequent dissociation processes. This is exemplified on benchmark systems, trimetallo-dodecacarbonyls M 3 (CO) 12 with M = Ru, Os, where the energy remaining in the molecule after photoionization can be retrieved by measuring the degree of fragmentation of the molecular ion. The intensity of different mass peaks can thus be directly related to ionization cross sections obtained by photoelectron spectroscopy. We find that the M-CO dissociation energy rises as the number of CO ligands decreases due to dissociation. Moreover, ionization of the CO ligands has a higher cross section than that of the metal center for both single and double ionization. After advanced fragmentation, a CO bond can break and the carbon atom remains bonded to the metal core. In addition, we found that the valence ionization cross sections of M 3 (CO) 12 are maximal at about 40 eV photon energy thus showing a more pronounced shape resonance than Ru and Os-complexes with a single metal atom center. Finally, an np → nd giant resonance absorption causes a significant increase of the ionization cross section above 50 eV for Ru 3 (CO) 12 . C 2015 AIP Publishing LLC. [http://dx

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“…In all transformations from photoelectron energies to photon energies and vice versa, we have used the values of the adiabatic ionization potentials given in Table 2. 63 , Green dashed-dotted: continuum multiple scattering method (CMSM) 15 , Orange solid: multichannel Schwinger configuration interaction (MCSCI) ten-channel 18 , Black thick solid: DFT method using a LB94 functional (this work), Black dashed thick: DFT method using a LDA functional (this work), Red thick solid: TDDFT method using a LDA functional (this work).…”

Section: Total Photoionization Cross Sectionsmentioning

confidence: 99%

Vibrational branching ratios in the photoelectron spectra of N2 and CO: interference and diffraction effects

Plésiat

Decleva

Martín

2012

Phys. Chem. Chem. Phys.

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Esta es la versión de autor del artículo publicado en: This is an author produced version of a paper published in: We present a detailed account of existing theoretical methods specially designed to provide vibrationally resolved photoionization cross sections of simple molecules within the Born-Oppenheimer approximation, with emphasis on newly developed methods based on density functional theory. The performance of these methods is shown for the case of N 2 and CO photoionization. Particular attention is paid to the region of high photon energies, where the electron wavelength is comparable to the bond length and, therefore, two-center interferences and diffraction are expected to occur. As shown in a recent work [Canton et al., Proc. Natl. Acad. Sci., 2011, 108, 73027306], the main experimental difficulty, which is to extract the relatively small diffraction features from the rapidly decreasing cross section, can be easily overcome by determining ratios of vibrationally resolved photoelectron spectra and existing theoretical calculations. From these ratios, one can thus get direct information about the molecular geometry. In this work, results obtained in a wide range of photon energies and for many different molecular orbitals of N 2 and CO are discussed and compared with the available experimental measurements. From this comparison, limitations and further possible improvements of the existing theoretical methods are discussed. The new results presented in the manuscript confirm that the conclusions reported in the above reference are of general validity.

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Shape Resonances inK-Shell Photoionization of Diatomic Molecules

Cited by 344 publications

References 10 publications

Experimental characterization of the Xe 5p photoionization by angle- and spin-resolved photoelectron spectroscopy

Experimental characterization of the Xe 5p photoionization by angle- and spin-resolved photoelectron spectroscopy

Ionization and photofragmentation of Ru3(CO)12 and Os3(CO)12

Vibrational branching ratios in the photoelectron spectra of N2 and CO: interference and diffraction effects

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