Simulations of Two-Photon Absorption Spectra of Fluorescent Dyes: The Impact of Non-Condon Effects
Journal of Chemical Theory and Computation,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 26, 2025
Computer
simulations
play
a
pivotal
role
in
interpreting
experimental
two-photon
absorption
(2PA)
spectra.
One
of
the
key
aspects
simulation
these
spectra
is
to
take
into
account
vibrational
fine
structure
bands
electronic
This
typically
done
by
employing
Franck–Condon
(FC)
term
and
low-order
terms
Herzberg–Teller
(HT)
expansion.
In
this
work,
we
present
systematic
study
first-order
HT
effects
on
vibronic
π
→
π*
2PA
13
common
fluorophores.
We
begin
evaluating
performance
several
density
functional
approximations
(DFAs)
against
second-order
coupled
cluster
singles
doubles
model
(CC2)
for
reproducing
transition
moments
their
first-
derivatives
with
respect
normal
modes
vibration
set
six
donor–acceptor
molecules.
Our
findings
reveal
that
most
DFAs
produce
inaccurate
values
derivatives,
exception
LC-BLYP
functionals
range–separation
parameters
0.33
0.47.
Although
underestimate
contribution
total
intensities
bands,
they
offer
reasonable
qualitative
reproduction
reference
further
explore
fluorescent
chromophores,
finding
contributions
are
secondary
FC
effects,
leading
small
shifts
wavelengths
peaks,
minimal
changes
intensities.
Additionally,
adiabatic
Hessian,
vertical
gradient
models
assessed.
The
general
agreement
among
confirms
harmonic
approximation
suitable
studying
selected
Язык: Английский
Excited-State Absorption: Reference Oscillator Strengths, Wave Function, and TDDFT Benchmarks
Journal of Chemical Theory and Computation,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 14, 2025
Excited-state
absorption
(ESA)
corresponds
to
the
transition
between
two
electronic
excited
states
and
is
a
fundamental
process
for
probing
understanding
light-matter
interactions.
Accurate
modeling
of
ESA
indeed
often
required
interpret
time-resolved
experiments.
In
this
contribution,
we
present
dataset
53
oscillator
strengths
in
three
different
gauges
associated
vertical
energies
71
21
small-
medium-sized
molecules
from
QUEST
database.
few
cases,
additionally
investigated
effect
geometry
relaxation
on
excited-state
geometries.
The
reference
values
were
obtained
within
quadratic
response
(QR)
CC3
formalism
using
eight
Dunning
basis
sets.
We
found
that
d-aug-cc-pVTZ
set
always
adequate
while
its
more
compact
double-ζ
counterpart,
d-aug-cc-pVDZ,
performs
well
most
cases.
These
QR-CC3
data
allow
us
assess
performance
QR-TDDFT,
with
without
applying
Tamm-Dancoff
approximation,
panel
global
range-separated
hybrids
(B3LYP,
BH&HLYP,
CAM-B3LYP,
LC-BLYP33,
LC-BLYP47),
as
several
lower-order
wave
function
methods,
i.e.,
QR-CCSD,
QR-CC2,
EOM-CCSD,
ISR-ADC(2),
ISR-ADC(3).
show
QR-TDDFT
delivers
acceptable
errors
CAM-B3LYP
showing
particular
promise,
especially
largest
our
set,
Franck-Condon
(FC)
region.
also
find
ISR-ADC(3)
exhibits
excellent
When
optimal
geometries,
relative
function-based
approaches
remains
consistent
trends
observed
However,
TD(A)-DFT,
accuracy
varies
significantly,
exchange-correlation
functionals
significantly
depends
chosen
geometry.
Язык: Английский
Performance of Density Functional Approximations in Calculations of Electronic Two-Photon Transition Strengths of Fluorescent Dyes
The Journal of Physical Chemistry A,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 24, 2025
The
performance
of
B3LYP,
PBE0,
and
CAM-B3LYP
functionals
in
the
prediction
two-photon
transition
strengths
(for
low-energy
transitions)
18
dipolar
donor-acceptor
systems
containing
a
difluoroborate
moiety
was
evaluated
against
results
obtained
using
resolution-of-identity
implementation
coupled-cluster
CC2
model.
generalized
few-state
model
approach,
which
strength
is
expressed
terms
electronic
structure
parameters,
i.e.,
excitation
energies,
dipole
moments,
applied
to
gain
deeper
insight
into
behavior
selected
exchange-correlation
functionals.
show
that
all
three
provide
differ
significantly
from
reference
strengths,
especially
case
molecules
exhibiting
highest
2PA
strength.
Язык: Английский
Computing Excited States of Very Large Systems with Range-Separated Hybrid Functionals and the Exact Integral Simplified Time-Dependent Density Functional Theory (XsTD-DFT)
The Journal of Physical Chemistry Letters,
Год журнала:
2024,
Номер
unknown, С. 12628 - 12635
Опубликована: Дек. 17, 2024
Simplified
quantum
chemistry
(sQC)
methods
can
routinely
compute
excited
states
for
very
large
systems
in
an
"all-atom"
fashion.
They
are
viable
alternatives
to
regular
multiscale
schemes.
sQC
have
the
advantage
of
accounting
explicitly
all
environment
at
a
mechanical
(QM)
level.
The
treatment
charge-transfer
is
now
improved
by
native
implementation
range-separated
hybrid
(RSH)
exchange-correlation
functionals
into
eXact
integral
simplified
time-dependent
density
functional
theory
(XsTD-DFT).
After
RSH
XsTD-DFT/TDA
scheme
was
benchmarked,
XsTD-DFT(/TDA)
ultraviolet/visible
absorption,
circular
dichroism
(CD),
and/or
two-photon
absorption
(2PA)
spectra
were
directly
compared
results
experiments
four
challenging
and
increasingly
systems:
eYFP
model
system,
Λ-shaped
multimodular
D-π-A-π-D'-π-A-π-D
chromophore,
mixed
donor/acceptor
ligand
Pd(II)
double
cage
[3BF
Язык: Английский