Fukunaga Hiroo, Fedorov Dmitri G, Chiba Mahito, Nii Kazumi, Kitaura Kazuo
Imaging Technology Center, Research & Development Management Headquarters, FUJIFILM Corporation, FFTP M0-6F, 1250, Takematsu, Minamiashigara-shi, Kanagawa 250-0111, Japan.
J Phys Chem A. 2008 Oct 30;112(43):10887-94. doi: 10.1021/jp804943m. Epub 2008 Oct 4.
Quinacridones (QAs) are organic hydrogen-bonded pigments, which are yellow in solution and become reddish to violet in solid phase depending on the crystal structure. We have carried out regular and fragment molecular orbital (FMO) based time-dependent density functional theory (TDDFT) calculations of the alpha (I), beta, and gamma crystalline phases of QA to examine the origin of the spectral shift in the solid phase. On the basis of the TDDFT calculations, we have found that the spectral shift from gas to solid phase in QA is dominated by the interplay of the structural deformation, electrostatic potential (crystal field), and intermolecular interactions, and each contribution is of the same order of magnitude. The spectral shift induced by the structural deformation is mainly caused by the stretch of the CO bond. The individual intermolecular interactions contribute to bathochromic and hypsochromic shifts depending on the spatial orientation, and their sums result in the bathochromic shift overall.
