Journal of Physics B Atomic Molecular and Optical Physics,
Год журнала:
2022,
Номер
55(4), С. 044001 - 044001
Опубликована: Фев. 16, 2022
Abstract
We
report
on
the
C
K-edge
x-ray
absorption
spectra
and
resonant
(RXES)
non-resonant
(NXES)
emission
of
ethylene,
allene
butadiene
in
gas
phase.
The
RXES
NXES
show
clear
differences
for
different
molecules.
Overall
both
types
are
more
structured
ethylene
allene,
than
butadiene.
Using
density
functional
theory–restricted
open
shell
configuration
interaction
single
calculations,
we
simulate
with
remarkable
agreement
experiment.
identify
spectral
features
as
being
due
to
transitions
involving
localised
1s
orbitals.
For
there
distinct
bands
that
reflect
predominantly
from
either
central
or
terminal
carbon
atoms.
These
results
discussed
context
ultrafast
studies
aimed
at
detecting
passage
through
conical
intersections
polyatomic
Communications Physics,
Год журнала:
2024,
Номер
7(1)
Опубликована: Янв. 2, 2024
Abstract
Time-resolved
X-ray
photoelectron
spectroscopy
(TXPS)
is
a
well-established
technique
to
probe
coherent
nuclear
wavepacket
dynamics
using
both
table-top
and
free-electron-based
ultrafast
lasers.
Energy
resolution,
however,
becomes
compromised
for
very
short
pulse
duration
in
the
sub-femtosecond
range.
By
resonantly
tuning
core-excited
states
undergoing
Auger
decay,
this
drawback
of
TXPS
can
be
mitigated.
While
resonant
Auger-electron
(RAS)
recover
vibrational
structures
not
hidden
by
broadband
excitation,
full
reconstruction
standing
challenge.
Here,
we
theoretically
demonstrate
how
complete
information
wavepacket,
i.e.,
populations
relative
phases
constituting
retrieved
from
time-resolved
RAS
(TRAS)
measurements.
Thus,
TRAS
offers
key
insights
into
coupled
electronic
complex
systems
on
ultrashort
timescales,
providing
an
alternative
leverage
femtosecond
attosecond
pulses.
Understanding
quantum
materials—solids
in
which
interactions
among
constituent
electrons
yield
a
great
variety
of
novel
emergent
phenomena—is
forefront
challenge
modern
condensed
matter
physics.
This
goal
has
driven
the
invention
and
refinement
several
experimental
methods,
can
spectroscopically
determine
elementary
excitations
correlation
functions
that
material
properties.
Here
we
focus
on
future
theoretical
trends
resonant
inelastic
x-ray
scattering
(RIXS),
is
remarkably
versatile
rapidly
growing
technique
for
probing
different
charge,
lattice,
spin,
orbital
materials.
We
provide
forward-looking
introduction
to
RIXS
outline
how
this
poised
deepen
our
insight
into
nature
materials
their
electronic
phenomena.
Published
by
American
Physical
Society
2024
Communications Physics,
Год журнала:
2022,
Номер
5(1)
Опубликована: Апрель 6, 2022
Abstract
When
materials
are
exposed
to
X-ray
pulses
with
sufficiently
high
intensity,
various
nonlinear
effects
can
occur.
The
most
fundamental
one
consists
of
stimulated
electronic
decays
after
resonant
absorption
X-rays.
Such
enhance
the
number
emitted
photons
and
emission
direction
is
confined
that
stimulating
incident
which
clone
themselves
in
process.
Here
we
report
observation
elastic
(REXS)
inelastic
(RIXS)
scattering
near
cobalt
L
3
edge
solid
Co/Pd
multilayer
samples.
We
observe
an
enhancement
order
10
6
over
conventional
spontaneous
RIXS
signal
into
small
acceptance
angle
spectrometer.
also
find
solids
both
REXS
spectra
contain
contributions
from
electron
processes,
even
for
ultrashort
5
fs
pulses.
Our
results
reveal
potential
caveats
development
condensed
matter.
Structural Dynamics,
Год журнала:
2023,
Номер
10(3)
Опубликована: Май 1, 2023
We
present
spatially
resolved
measurements
of
the
temperature
a
flat
liquid
water
microjet
for
varying
ambient
pressures,
from
vacuum
to
100%
relative
humidity.
The
entire
jet
surface
is
probed
in
single
shot
by
high-resolution
infrared
camera.
Obtained
2D
images
are
substantially
influenced
apparatus
on
opposite
side
camera;
protocol
correct
thermal
background
radiation
presented.
In
vacuum,
we
observe
cooling
rates
due
evaporation
order
10
Resonant
inelastic
x-ray
scattering
(RIXS)
is
a
major
method
for
investigation
of
electronic
structure
and
dynamics,
with
applications
ranging
from
basic
atomic
physics
to
materials
science.
In
RIXS
applied
inversion-symmetric
systems,
it
has
generally
been
accepted
that
strict
parity
selectivity
applies
in
the
sub–kilo–electron
volt
region.
contrast,
we
show
selection
rule
violated
spectra
free
homonuclear
diatomic
O
2
molecule.
By
analyzing
spectral
dependence
on
angle,
demonstrate
violation
due
phase
difference
coherent
at
two
sites,
analogy
Young’s
double-slit
experiment.
The
result
also
implies
interpretation
absorption
inversion
symmetric
molecules
this
energy
range
must
be
revised.
Nature Communications,
Год журнала:
2022,
Номер
13(1)
Опубликована: Ноя. 22, 2022
The
concomitant
motion
of
electrons
and
nuclei
on
the
femtosecond
time
scale
marks
fate
chemical
biological
processes.
Here
we
demonstrate
ability
to
initiate
track
ultrafast
electron
rearrangement
bond
breaking
site-specifically
in
real
for
carbon
monoxide
diatomic
molecule.
We
employ
a
local
resonant
x-ray
pump
at
oxygen
atom
probe
shifts
core-electron
binding
energy.
observe
charge
redistribution
accompanying
core-excitation
followed
by
Auger
decay,
eventually
leading
dissociation
hole
trapping
one
site
presented
technique
is
general
nature
with
sensitivity
environment
changes
including
transient
electronic
excited
state
dynamics.
This
work
provides
route
investigate
energy
transport
processes
more
complex
systems
tracking
selective
their
natural
timescale.
The Journal of Physical Chemistry C,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 1, 2025
In
this
work,
we
present
a
comprehensive
study
of
the
luminescence
relaxation
mechanism
and
associated
spectral
broadening
in
series
Eu2+-doped
narrow-band
phosphors.
It
is
highlighted
that
commonly
used
full-width
at
half-maximum
(fwhm)
no
longer
sensitive
measure
for
quantifying
emission
bandwidth
these
materials.
A
thorough
understanding
factors
contributing
to
narrow
requires
an
explicit
treatment
magnetic
structure
ground
emissive
excited
state
manifolds.
This
incorporating
spin–orbit
coupling
effects
using
wave
function-based
methods
such
as
complete
active
space
self-consistent
field
combined
with
second-order
N-electron
valence
perturbation
theory
(CASSCF/NEVPT2).
addition,
dynamics
calculations,
one
needs
consider
vibronic
interactions
on
basis
Franck–Condon
(FC),
Herzberg–Teller
(HT),
and,
when
necessary,
pseudo
Jahn–Teller
(PJT)
effects.
Our
analysis
underscores
controlling
synergistic
roles
"static"
"dynamic"
are
essential
accurately
assessing
band
systems.
We
show
results
can,
principle,
be
generalized
arbitrary
set
phosphor
candidates
can
potentially
aid
experimental
efforts
toward
developing
novel
phosphors
enhanced
luminescent
properties.
