4 research outputs found
Azimuthons in weakly nonlinear waveguides of different symmetries
We show that weakly guiding nonlinear waveguides support stable propagation
of rotating spatial solitons (azimuthons). We investigate the role of waveguide
symmetry on the soliton rotation. We find that azimuthons in circular
waveguides always rotate rigidly during propagation and the analytically
predicted rotation frequency is in excellent agreement with numerical
simulations. On the other hand, azimuthons in square waveguides may experience
spatial deformation during propagation. Moreover, we show that there is a
critical value for the modulation depth of azimuthons above which solitons just
wobble back and forth, and below which they rotate continuously. We explain
these dynamics using the concept of energy difference between different
orientations of the azimuthon.Comment: 12 pages, 8 figure
A Unified Picture of S* in Carotenoids
In
π-conjugated chain molecules such as carotenoids, coupling
between electronic and vibrational degrees of freedom is of central
importance. It governs both dynamic and static properties, such as
the time scales of excited state relaxation as well as absorption
spectra. In this work, we treat vibronic dynamics in carotenoids on
four electronic states (|S<sub>0</sub>⟩, |S<sub>1</sub>⟩,
|S<sub>2</sub>⟩, and |S<sub>n</sub>⟩) in a physically
rigorous framework. This model explains all features previously associated
with the intensely debated S* state. Besides successfully fitting
transient absorption data of a zeaxanthin homologue, this model also
accounts for previous results from global target analysis and chain
length-dependent studies. Additionally, we are able to incorporate
findings from pump-deplete-probe experiments, which were incompatible
to any pre-existing model. Thus, we present the first comprehensive
and unified interpretation of S*-related features, explaining them
by vibronic transitions on either S<sub>1</sub>, S<sub>0</sub>, or
both, depending on the chain length of the investigated carotenoid
A Unified Picture of S* in Carotenoids
D.A. and V.B. acknowledge the support from the Research
Council of Lithuania(MIP-090/2015 and MIP-090/2016). T.P.
thanks the Czech Science Foundation (Grant No. 16-10417S)
for financial support. A. G. P. and J. H. acknowledge funding by
the Austrian Science Fund (FWF): START project Y631−N27