X-ray Raman Scattering Study of Aligned Polyfluorene

Galambosi, S.; Knaapila, Matti; Soininen, J. A.; Nygård, Kim; Huotari, Simo; Galbrecht, Frank; Scherf, Ullrich; Monkman, Andrew P.; Hämäläinen, K.

doi:10.1021/ma060823u

Cited by 23 publications

(27 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Commonality of isolated features in the l-DOS can be taken as a significant fingerprint for covalency, such as from a shared DOS from a hybridized antibonding molecular orbital. 23,24 Given the broad range of energy over which the s-and p-DOS are similar and given the absence of covalent character in α-Li 3 N, such an explanation is incorrect here.…”

Section: Ivb Excited Electronic Statesmentioning

confidence: 95%

The local electronic structure of α-Li3N

Fister

Seidler

Shirley

et al. 2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

New theoretical and experimental investigations of the occupied and unoccupied local electronic densities of states (DOS) are reported for alpha-Li(3)N. Band-structure and density-functional theory calculations confirm the absence of covalent bonding character. However, real-space full-multiple-scattering (RSFMS) calculations of the occupied local DOS find less extreme nominal valences than have previously been proposed. Nonresonant inelastic x-ray scattering, RSFMS calculations, and calculations based on the Bethe-Salpeter equation are used to characterize the unoccupied electronic final states local to both the Li and N sites. There is a good agreement between experiment and theory. Throughout the Li 1s near-edge region, both experiment and theory find strong similarities in the s-and p-type components of the unoccupied local final DOS projected onto an orbital angular momentum basis (l-DOS). An unexpected, significant correspondence exists between the near-edge spectra for the Li 1s and N 1s initial states. We argue that both spectra are sampling essentially the same final DOS due to the combination of long core-hole lifetimes, long photoelectron lifetimes, and the fact that orbital angular momentum is the same for all relevant initial states. Such considerations may be generally applicable for low atomic number compounds.

show abstract

Section: Ivb Excited Electronic Statesmentioning

confidence: 95%

The local electronic structure of α-Li3N

Fister

Seidler

Shirley

et al. 2008

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…This approach to the background subtraction was previously used and found to work well in Ref. 20. The experimental spectra were also corrected for absorption, detector dead time, and energy dependence of the incident flux, although these factors contribute only a few percent over the measured energy range.…”

Section: Methodsmentioning

confidence: 99%

“…XRS is a versatile technique that can be used to study the electronic structure of a variety of materials such as solids, 19 organic materials, 20 and liquids. 21 However, in contrast to XAS, the utilization of the XRS method enables the relative contributions of dipole versus non-dipole transitions in the spectra to be tuned by varying the momentum transfer during the scattering process.…”

Section: Introductionmentioning

confidence: 99%

Symmetry of the1score exciton in diamond studied using x-ray Raman scattering

et al. 2007

View full text Add to dashboard Cite

The detailed electronic structure of diamond has been studied by x-ray Raman scattering at the 1s excitation threshold. By combining the experimental high-resolution inelastic scattering spectra with a computational scheme based on the real-space multiple scattering approach, the symmetry-resolved s and p angular projected unoccupied local densities of states of diamond have been extracted. The results unambiguously show that the extensively studied diamond 1s core exciton has a p-like angular symmetry. Furthermore, the effects of various experimental and numerical uncertainties on the extraction scheme are carefully analyzed and discussed giving important insight to the applicability of this promising complementary technique to other systems.

show abstract

“…2,17 Theoretical methods for XAS calculation have recently been extended to full calculations of the q dependence of S͑q , ͒, 9,11,29 and the advent of the third-generation light sources together with improved XRS spectrometers has enabled a rapid growth of applications of q-dependent XRS. 3,15,16,18,19,21,28,[30][31][32] For polycrystalline materials, such as those investigated in this work, the core-electron contribution to S͑q , ͒ can be decomposed into a sum of contributions from final states with particular orbital angular momentum l,…”

Section: ͑2͒mentioning

confidence: 99%

“…2,17 XRS measurements have been used to determine the orbital angular momentum of excitons and other resonances in several materials. 2,3,[18][19][20][21] Here, we report new XRS measurements of the q dependence of excitonic features associated with the Na 1s initial states of NaCl and NaF. The optical and electronic properties of alkali halides have seen several decades of work and they serve as important test cases for understanding final-state effects in insulators.…”

Section: Introductionmentioning

confidence: 99%

Final-state symmetry ofNa 1score-shell excitons in NaCl and NaF

Nagle

Seidler

Shirley³

et al. 2009

Phys. Rev. B

View full text Add to dashboard Cite

We report measurements of the Na 1s contribution to the nonresonant inelastic x-ray scattering ͑NRIXS͒ from NaCl and NaF. Prior x-ray absorption studies have observed two pre-edge excitons in both materials. The momentum-transfer dependence ͑q dependence͒ of the measured NRIXS cross section and of real-space full multiple scattering and Bethe-Salpeter calculations determine that the higher-energy core excitons are s type for each material. The lower-energy core excitons contribute at most weakly to the NRIXS signal and we propose that these may be surface core excitons, as have been observed in several other alkali halides. The analysis of the orbital angular momentum of these features leads to a discussion of the limited sensitivity of NRIXS measurements to d-type final states when investigating 1s initial states. In this case the s-and p-type final density of states can be characterized by measurements at a small number of momentum transfers. This is in contrast to the case of more complex initial states for which measurements at a large number of momentum transfers are needed to separate the rich admixture of accessible and contributing final-state symmetries.

show abstract

X-ray Raman Scattering Study of Aligned Polyfluorene

Cited by 23 publications

References 42 publications

The local electronic structure of α-Li3N

The local electronic structure of α-Li3N

Symmetry of the1score exciton in diamond studied using x-ray Raman scattering

Final-state symmetry ofNa 1score-shell excitons in NaCl and NaF

Contact Info

Product

Resources

About