Configuration interaction simulation of the NEXAFS photoabsorption spectrum of naphthalene

Journal of the Brazilian Chemical Society

Hollauer, Eduardo¹  Rocco, Maria Luiza M.¹  Netto, Annibal D. Pereira¹  Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil¹  Universität Erlangen, Erlangen, Germany¹  Universidade Federal Fluminense, Niterói, Brazil¹  Prucole, Elísia dos Santos¹  Universität Würzburg, Würzburg, Germany¹  Schöll, Achim¹  Fink, Rainer¹ 

关键词: ab initio calculations;    photoabsorption spectroscopy;    NEXAFS;    naphthalene;   

DOI  :  10.1590/S0103-50532005000100005

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The near-edge X-ray absorption fine structure (NEXAFS) spectrum of naphthalene was analysed theoratically using the final state approximation rule. ROHF/SCF calculations were carried out for a localized core-hole cationic state under the Bagus-Schaffer scheme for each channel of inequivalent excitations. CI calculations were performed allowing single and double excitations from carbon 1s electrons to the first ten virtual orbitals. The energies and oscillator strengths were calculated. The final spectrum was generated by convolution of Gaussian peaks with 0.5 eV as FWHM of the statistically-averaged calculated transitions. The theoretical result shows remarkable agreement with the experimental high-resolution NEXAFS data measured at BESSY II. Work is in progress to get better control of the variational wave function collapse problem at CI level through the use of symmetry breaking core-hole excited states (MEG-CI). This methodology might offer a clear and transparent way to take into account the relaxational and correlation energy, the virtual orbital specificity and the required restricted configuration interaction needed to the NEXAFS prediction problem.

【 授权许可】

Unknown