Photoelectron Angular Distributions from O<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">K</mml:mi></mml:math>Shell of Oriented CO Molecules: A Critical Comparison between Theory and Experiment

Ito, Kenji; Adachi, Jiro; Hikosaka, Y.; Motoki, Shinichi; Soejima, K; Yagishita, Akira; Raşeev, G.; Cherepkov, N. A.

doi:10.1103/physrevlett.85.46

Cited by 38 publications

(49 citation statements)

References 15 publications

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“…At higher energies the RCHF approximation has also been used (CO 43,44,50,52,54,67,[115][116][117][118][119][120] , N 2 3 ). This is in contrast with the frozen core Hartree Fock (FCHF) approximation, which has widely been used in most earlier and some recent works (CO 42,48,58,74,75,106,121 , N 2 22,27,32,58,74,75,106 ).…”

Section: Theoretical Methods Within the Fixed-nuclei Approximationmentioning

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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Section: Theoretical Methods Within the Fixed-nuclei Approximationmentioning

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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“…The theoretical description of CO + states involved in the 22-40 eV energy region has been discussed previously for the interpretation of high resolution photoelectron spectrum (PES) spectra reported by Baltzer et al 26 Complementary results characterizing the CO inner-valence region have also been discussed in the experimental PES studies by Potts and Williams, 27 and Svensson et al 28 and in the calculations reported by Hayes and Nobel 29 and Ehara et al 30 Valence MFPADs have been studied for CO molecules absorbed on surfaces using circularly polarized light 31 and linearly polarized light. 32 Additionally, MFPADs in core shell ionization have been studied using circularly 33,34 or linearly 35,36 polarized light. However to our knowledge, only the PAD results of Hikosaka and Eland 37 and Eland et al 38 using the velocity imaging photoionization coincidence technique have been reported in the literature for PI of inner-valence states, in particular the 4 2 + state.…”

Section: Introductionmentioning

confidence: 99%

Valence and inner-valence shell dissociative photoionization of CO in the 26–33 eV range. II. Molecular-frame and recoil-frame photoelectron angular distributions

Lebech

Houver

Raşeev

et al. 2012

The Journal of Chemical Physics

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Experimental and theoretical results for molecular-frame photoemission are presented for inner-valence shell photoionization of the CO molecule induced by linearly and circularly polarized light. The experimental recoil frame photoelectron angular distributions (RFPADs) obtained from dissociative photoionization measurements where the velocities of the ionic fragment and photoelectron were detected in coincidence, are compared to RFPADs computed using the multichannel Schwinger configuration interaction method. The formalism for including a finite lifetime of the predissociative ion state is presented for the case of general elliptically polarized light, to obtain the RFPAD rather than the molecular frame photoelectron angular distribution (MFPAD), which would be obtained with the assumption of instantaneous dissociation. We have considered photoionization of CO for the photon energies of 26.0 eV, 29.5 eV, and 32.5 eV. A comparison of experimental and theoretical RFPADs allows us to identify the ionic states detected in the experimental studies. In addition to previously identified states, we found evidence for the 2 (2)Δ state with an ionization potential of 25.3 eV and (2)Σ(+) states with ionization potentials near 32.5 eV. A comparison of the experimental and theoretical RFPADs permits us to estimate predissociative lifetimes of 0.25-1 ps for some of the ion states. Consideration of the MFPADs of a series of (2)Π ion states indicates the importance of inter-channel coupling at low photoelectron kinetic energy and the limitations of a single-channel analysis based on the corresponding Dyson orbitals.

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“…But only recently, owing to application of high intensity synchrotron radiation sources and highly sophisticated electron and ion detectors, it became possible to measure the partial photoionization cross sections and angular distributions with unprecedented overall resolution of about 0.1 eV sufficient to resolve the vibrational structure of the photoelectron spectra 2. By using an angle‐resolved photoelectron–photoion coincidence technique it became possible to select the processes corresponding to a well‐defined direction of the molecular axis in space from the photoionization of an ensemble of randomly oriented molecules 3–10. The direction of motion of the fragment ion gives the direction of the molecular axis at the moment of photoionization, provided the dissociation time is much shorter than the period of molecular rotation.…”

Section: Introductionmentioning

confidence: 99%

New developments in the theory of molecular K‐shell photoionization

Cherepkov

Semenov

2007

Int J of Quantum Chemistry

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ABSTRACT:A new version of the relaxed core Hartree-Fock approximation with a fractional charge of the molecular ion state is applied for calculations of molecular photoionization processes. The set of continuous spectrum wave functions obtained by that method is used when taking many-electron correlations into account in the framework of the random-phase approximation. The vibrational motion is also included into consideration. In that way, the most reliable results for the vibrationally resolved partial photoionization cross sections and the angular asymmetry parameter ␤ for the K-shells of CO and N 2 molecules have been obtained. A good agreement with the stateof-the-art experimental data is demonstrated. From our calculations it follows that the nondipole effects for the K-shells of N 2 and CO molecules are small near the ionization thresholds, in agreement with the latest experimental data. Two predictions have been made based on these calculations. One of them is the appearance of the correlational maximum in the photoionization cross section of the 1 u shell of N 2 molecule near the * shape resonance, which is now fully confirmed by the experiment. The second prediction concerns the behavior of the nondipole parameters for the 1 g and 1 u shells of N 2 . According to our calculation, they oscillate in antiphase with rather large amplitudes around the unresolved values, so that after summation of the contributions of the two K-shells, the oscillations practically disappear. This prediction does not yet have an experimental confirmation.

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Photoelectron Angular Distributions from OKShell of Oriented CO Molecules: A Critical Comparison between Theory and Experiment

Cited by 38 publications

References 15 publications

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

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

Valence and inner-valence shell dissociative photoionization of CO in the 26–33 eV range. II. Molecular-frame and recoil-frame photoelectron angular distributions

New developments in the theory of molecular K‐shell photoionization

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