Molecular excited states have complex electronic structure. For the theoretical
study of the molecular excited states, it is relevant to describe these
electronic states precisely. We developed the highly accurate SAC-CI general-R
theory which can describe even multi-electron processes and enabled reliable
theoretical spectroscopy of the molecular excited states. We also implemented
the analytical energy gradients of the general-R method. We are working
on the development of useful and accurate electronic structure theory.
Development of Active Space Method (Details)
Recent development of the high-resolution molecular spectroscopy has enabled
the measurement of the detailed structures in the electronic spectra and
new phenomena. For the interpretation of these spectra and photo-electronic
phenomena, reliable theoretical information is indispensable. We have investigated
various kinds of molecular spectroscopy from the valence excited states
to the inner-shell electronic processes in wide energy region. For examples,
we studied satellite spectra, vibrational spectra, structure relaxation,
and valence-Rydberg coupling in the study of core-electronic processes.
We are aiming at new dimension of theoretical spectroscopy based on the
accurate electronic structure theory.
Core-Electronic Processes (Details)
For the photofunctional materials, molecular excited states are essential
and the theoretical study can clarify the details of the photophysical
property of the molecules. We have investigated the excited states and
electronic processes of the organic light emitting diodes (OLED) and the
biological chemosensor. We showed that the thermal distribution due to
the flexible structure is relevant in the electronic spectra of fluorene-thiophene.
We also found that for the biological chemosensor the excited-state dynamics
in solution is essential. We study the electronic processes of photofunctional
molecules using the accurate electronic structure theory.
Organic Light-Emitting Diodes (Details)
The chemical reaction on the metal surface is a phenomenon at the junction of the
finite and infinite systems. The interaction between the surface and adsorbates
is essential, and therefore the theoretical model describing the surface-molecule
interaction is a key issue for the theoretical study of chemical reactions
on the surface. We have investigated the surface reactions like methanol
dehydrogenation reaction on the Pt surface used in direct methanol fuel
cell (DMFC). We are also interested in the surface photochemistry.
