TY - JOUR

T1 - Experimental and theoretical study of X-ray K edges absorption spectra of carbon and nitrogen in the phthalocyanine H2Pc molecule

AU - Semushkina, G. I.

AU - Mazalov, L. N.

AU - Basova, T. V.

PY - 2016/12/1

Y1 - 2016/12/1

N2 - The study of the electronic structure of H2Pc was carried out to examine the structure of the lowest unoccupied molecular orbitals (LUMO) of molecule phthalocyanine by X-ray absorption spectroscopy using quantum-chemical calculations. The theoretical calculations were performed on the stationary theory (frozen orbital approximation, Z+1 model) and time-dependent density functional theory (TDDFT). A consideration of K edges absorption spectra of carbon and nitrogen in the common scale of binding energies allows estimating the contributions of AO of all phthalocyanine atoms to the LUMO, defining the sequence of levels, the binding energies of the corresponding levels, and also the character of electronic interactions between individual atoms. It was shown that the best agreement between the experimental and theoretical pre-edge structures of the absorption spectra of nitrogen and carbon for H2Pc is observed in the case of the application of stationary density functional theory in Z+1 model to account for an X-ray hole. In this case the 2pπ AO of the Nα(1,2) and Сα atoms make a predominant contribution to the LUMO. The 2pπ AO of the Nα(1,2) atoms mainly contribute to the boundary LUMO with the energy ~–2.3 eV.

AB - The study of the electronic structure of H2Pc was carried out to examine the structure of the lowest unoccupied molecular orbitals (LUMO) of molecule phthalocyanine by X-ray absorption spectroscopy using quantum-chemical calculations. The theoretical calculations were performed on the stationary theory (frozen orbital approximation, Z+1 model) and time-dependent density functional theory (TDDFT). A consideration of K edges absorption spectra of carbon and nitrogen in the common scale of binding energies allows estimating the contributions of AO of all phthalocyanine atoms to the LUMO, defining the sequence of levels, the binding energies of the corresponding levels, and also the character of electronic interactions between individual atoms. It was shown that the best agreement between the experimental and theoretical pre-edge structures of the absorption spectra of nitrogen and carbon for H2Pc is observed in the case of the application of stationary density functional theory in Z+1 model to account for an X-ray hole. In this case the 2pπ AO of the Nα(1,2) and Сα atoms make a predominant contribution to the LUMO. The 2pπ AO of the Nα(1,2) atoms mainly contribute to the boundary LUMO with the energy ~–2.3 eV.

KW - phthalocyanine

KW - stationary and time-dependent density functional theory

KW - X-ray absorption spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85009997612&partnerID=8YFLogxK

U2 - 10.1134/S0022476616070064

DO - 10.1134/S0022476616070064

M3 - Article

AN - SCOPUS:85009997612

VL - 57

SP - 1334

EP - 1347

JO - Journal of Structural Chemistry

JF - Journal of Structural Chemistry

SN - 0022-4766

IS - 7

ER -