We propose a new approach for calculating
the change of the absorption spectrum of a molecule when moved from
the gas phase to a crystalline morphology. The so-called gas-to-crystal
shift Δm is mainly caused by dispersion effects and depends
sensitively on the molecule’s specific position in the nanoscopic
setting. Using an extended dipole approximation, we are able to divide
Δm= −QWm in two factors, where Q depends only on the
molecular species and accounts for all nonresonant electronic transitions
contributing to the dispersion while Wm is a geometry factor expressing the site dependence of the shift
in a given molecular structure. The ability of our approach to predict
absorption spectra is demonstrated using the example of polycrystalline
films of 3,4,9,10-perylenetetracarboxylic diimide (PTCDI).
We report on the impact of partial fluorination of para-sexiphenyl (6P) on the growth mode when deposited on the non-polar ZnO(101̄0) surface. The evolution of the thin film structure and morphology is monitored by in situ atomic force microscopy and in situ real-time X-ray scattering. Both 6P and its symmetrical, terminally fluorinated derivative (6P-F4) grow in a highly crystalline mode, however, with a distinctly different morphology. While 6P films are characterised by the formation of two different phases with three-dimensional nanocrystallites and consequently a rather rough surface morphology, layer-by-layer growth and phase purity in case of 6P-F4 prevails leading to smooth terraced thin films. We relate the different growth behaviour to specifics of the thin film structure.
Combining rigorous quantum epitaxial design, highly accurate growth, novel processing and thermal management pushes the output power of single chip vertical‐external‐cavity surface‐emitting lasers (VECSELs) beyond the 100 W milestone.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.