Effects of π -stacking interactions on the near carbon K -edge x-ray absorption fine structure : A theoretical study of the ethylene pentamer and the phthalocyanine dimer

• X-ray absorption spectra have been determined for ethylene and free base phthalocyanine at the carbon K -edge with use of the complex polarization propagator method combined with Kohn-Sham density functional theory and the Coulomb attenuated method B3LYP exchange-correlation functional. Apart from isolated molecules, the study includes π -stacked systems of the phthalocyanine dimer and the ethylene dimer, trimer, tetramer, and pentamer. For ethylene, π -stacking involves a reduction in transition energy of the valence π* -band by some 70 meV and large spectral changes (regarding also shape and intensity) of the Rydberg bands. For phthalocyanine, there are large spectral changes in the entire valence π * -part of the spectrum. © 2009 American Institute of Physics.

Ämnesord

NATURVETENSKAP  -- Kemi -- Teoretisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Theoretical Chemistry (hsv//eng)

Nyckelord

Absorption

Ethylene

Spectrum analysis

X ray absorption

Carbon k edges

Complex polarization propagators

Density functional

Ethylene dimers

Exchange-correlation functional

Free base

Isolated molecules

Pentamer

Phthalocyanine dimers

Rydberg

Spectral changes

Stacked systems

Stacking interactions

Tetramer

Theoretical studies

Transition energies

X-ray absorption fine structures

X-ray absorption spectrum

Density functional theory

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