Beyond CCSD(T) Accuracy at Lower Scaling with Auxiliary Field Quantum Monte Carlo
Journal of Chemical Theory and Computation,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 5, 2025
We
introduce
a
black-box
auxiliary
field
quantum
Monte
Carlo
(AFQMC)
approach
to
perform
highly
accurate
electronic
structure
calculations
using
configuration
interaction
singles
and
doubles
(CISD)
trial
states.
This
method
consistently
provides
more
energy
estimates
than
coupled
cluster
with
perturbative
triples
(CCSD(T)),
often
regarded
as
the
gold
standard
in
chemistry.
level
of
precision
is
achieved
at
lower
asymptotic
computational
cost,
scaling
O(N6)
compared
O(N7)
CCSD(T).
provide
numerical
evidence
supporting
these
findings
through
results
for
challenging
main
group
transition
metal-containing
molecules.
Язык: Английский
Benchmarking Molecular and Periodic Extended Tight Binding Methods for Spin-State Energies in Spin-Crossover Systems
The Journal of Physical Chemistry C,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 13, 2025
Язык: Английский
Predicting Spin States of Iron Porphyrins with DFT Methods Including Crystal Packing Effects and Thermodynamic Corrections
Physical Chemistry Chemical Physics,
Год журнала:
2024,
Номер
26(26), С. 18182 - 18195
Опубликована: Янв. 1, 2024
Which
DFT
methods
can
most
reliably
predict
the
observed
spin
state
in
iron
porphyrins
with
thermodynamics
and
crystal
packing
included?
Язык: Английский
Projector‐Based Quantum Embedding Study of Iron Complexes
Journal of Computational Chemistry,
Год журнала:
2025,
Номер
46(3)
Опубликована: Янв. 29, 2025
ABSTRACT
Projection‐based
embedding
theory
(PBET)
is
used
to
calculate
and
assess
the
challenging
spin‐crossover
energies
for
a
selection
of
small
Fe‐containing
systems
by
metal
center
into
frozen
potential
ligands.
MP2,
CCSD,
CCSD(T)
are
embedded
in
potentials
from
SCAN
r
2
functionals
compared
with
canonical
values
constituent
methods
previously
reported
reference
values.
Considering
PBET
calculations
as
correction
underlying
DFT,
able
provided
improvement
most
cases.
In
some
cases,
compensate
limitations
wave
function
produce
results
similar
more
rigorous
literature.
For
near
zero,
current
methodology
fails
provide
consistent
improvement.
The
isolated
recalculation
electronic
structure
around
when
DFT
treatment
ligand
field
shows
promise
pragmatic
lower
cost
whole
system
difficult
class
complexes.
Язык: Английский
Performance of Quantum Chemistry Methods for Benchmark Set of Spin–State Energetics Derived from Experimental Data of 17 Transition Metal Complexes (SSE17)
Chemical Science,
Год журнала:
2024,
Номер
15(48), С. 20189 - 20204
Опубликована: Янв. 1, 2024
Accurate
prediction
of
spin-state
energetics
for
transition
metal
(TM)
complexes
is
a
compelling
problem
in
applied
quantum
chemistry,
with
enormous
implications
modeling
catalytic
reaction
mechanisms
and
computational
discovery
materials.
Computed
are
strongly
method-dependent
credible
reference
data
scarce,
making
it
difficult
to
conduct
conclusive
studies
open-shell
TM
systems.
Here,
we
present
novel
benchmark
set
first-row
energetics,
which
derived
from
experimental
17
containing
FeII,
FeIII,
CoII,
CoIII,
MnII,
NiII
chemically
diverse
ligands.
The
estimates
adiabatic
or
vertical
splittings,
obtained
spin
crossover
enthalpies
energies
spin-forbidden
absorption
bands,
suitably
back-corrected
the
vibrational
environmental
effects,
employed
as
values
benchmarking
density
functional
theory
(DFT)
wave
function
methods.
results
demonstrate
high
accuracy
coupled-cluster
CCSD(T)
method,
features
mean
absolute
error
(MAE)
1.5
kcal
mol-1
maximum
-3.5
mol-1,
outperforms
all
tested
multireference
methods:
CASPT2,
MRCI+Q,
CASPT2/CC
CASPT2+δMRCI.
Switching
Hartree-Fock
Kohn-Sham
orbitals
not
found
consistently
improve
accuracy.
best
performing
DFT
methods
double-hybrids
(PWPB95-D3(BJ),
B2PLYP-D3(BJ))
MAEs
below
3
errors
within
6
whereas
so
far
recommended
states
(e.g.,
B3LYP*-D3(BJ)
TPSSh-D3(BJ))
perform
much
worse
5-7
beyond
10
mol-1.
This
work
first
such
extensive
study
chemistry
use
data.
relevant
proper
choice
characterize
systems
catalysis
(bio)inorganic
may
also
stimulate
new
developments
quantum-chemical
machine
learning
approaches.
Язык: Английский
Assessment of the applicability of DFT methods to [Cp*Rh]‐catalyzed hydrogen evolution processes
Journal of Computational Chemistry,
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 25, 2024
The
present
computational
study
provides
a
benchmark
of
density
functional
theory
(DFT)
methods
in
describing
hydrogen
evolution
processes
catalyzed
by
[Cp*Rh]-containing
organometallic
complexes.
A
test
set
was
composed
26
elementary
reactions
featuring
chemical
transformations
and
bonding
situations
essential
for
the
field,
including
emerging
concept
non-innocent
Cp*
behavior.
Reference
values
were
obtained
from
highly
accurate
3/4
complete
basis
6/7
PNO
space
extrapolated
DLPNO-CCSD(T)
energies.
performance
lower-level
extrapolation
procedures
also
assessed.
We
considered
84
functionals
(DF)
(including
13
generalized
gradient
approximations
(GGA),
nine
meta-GGAs,
33
hybrids,
29
double-hybrids)
three
composite
(HF-3c,
PBEh-3c,
r
Язык: Английский
Predicting Spin States of Iron Porphyrins with DFT Methods Including Crystal Packing Effects and Thermodynamic Corrections
Опубликована: Март 29, 2024
Accurate
computational
treatment
of
spin
states
for
transition
metal
complexes,
exemplified
by
iron
porphyrins,
lies
at
the
heart
quantum
bioinorganic
chemistry,
but
same
time
represents
a
great
challenge
approximate
density
functional
theory
(DFT)
methods,
which
are
predominantly
used.
Here,
accuracy
DFT
methods
spin–state
splittings
in
porphyrin
is
assessed
probing
ability
to
correctly
predict
ground
six
Fe(III)
or
Fe(II)
complexes
experimentally
characterized
solid
state.
For
each
case,
molecular
and
periodic
calculations
employed
quantify
effect
side
substituents
crystal
packing
(CPE)
on
splitting.
It
proposed
partition
total
CPE
into
additive
components,
direct
structural
one,
importance
shown
significantly
vary
from
case
case.
By
knowing
substituent
effect,
CPE,
Gibbs
free
energy
thermodynamic
correction
calculations,
one
can
employ
experimental
ground-state
information
order
derive
quantitative
constraint
electronic
difference
simplified
(porphin)
model
metalloporphyrin.
The
constraints
derived
such
way—in
form
single
double
inequalities—are
used
assess
dispersion-corrected
6
[Fe(III)(P)(2-MeIm)2]+,
[Fe(III)(P)(2-MeIm)]+,
[Fe(II)(P)(THF)2]
[Fe(II)(P)]
models
(where
P
porphin,
2-MeIm
2-methylimidazole,
THF
tetrahydrofuran).
These
data
constitute
new
benchmark
set
crystalline
porphyrins
(SSCIP6).
highest
obtained
double-hybrid
functionals
(B2PLYP-D3,
DSD-PBEB95-D3),
whereas
hybrid
functionals,
especially
those
with
reduced
admixture
exact
exchange
(B3LYP*-D3,
TPSSh-D3),
found
considerably
overstabilize
intermediate
state,
leading
incorrect
prediction
porphyrins.
present
approach,
be
generalized
other
not
only
useful
method
benchmarking,
also
sheds
light
interpretations
metalloporphyrins,
important
understand
properties
heme
proteins.
Язык: Английский
Notizen aus der Chemie
Nachrichten aus der Chemie,
Год журнала:
2024,
Номер
72(6), С. 52 - 55
Опубликована: Май 31, 2024
Performance of Quantum Chemistry Methods for Benchmark Set of Spin–State Energetics Derived from Experimental Data of 17 Transition Metal Complexes (SSE17)
Опубликована: Авг. 1, 2024
Reliable
prediction
of
spin-state
energetics
for
transition
metal
(TM)
complexes
is
recognized
as
a
challenging
and
compelling
problem
in
quantum
chemistry,
with
implications
modeling
catalytic
reaction
mechanisms
computational
discovery
materials.
The
computed
spin–state
are
highly
variable
the
choice
method
credible
reference
data
scarce,
making
it
difficult
to
conduct
conclusive
studies
open-shell
TM
systems.
Here,
we
present
novel
benchmark
set
first-row
energetics,
which
derived
from
curated
experimental
17
representative
containing
Fe(II),
Fe(III),
Co(II),
Co(III),
Mn(II),
Ni(II)
chemically
diverse
ligands.
values
adiabatic
or
vertical
energy
differences
spin-crossover
enthalpies
(9
complexes)
energies
spin-forbidden
absorption
bands
reflectance
spectra
(8
complexes).
These
carefully
back-corrected
relevant
vibrational
environmental
effects
(due
solvation
crystal
lattice)
order
provide
directly
comparable
electronic
differences.
new
makes
possible
assess
accuracy
approximate
density
functional
theory
(DFT)
wave
function
methods
level
statistical
reliability
not
attained
earlier
studies.
lowest
mean
absolute
error
(MAE)
1.5
kcal/mol
maximum
−3.5
found
coupled-cluster
CCSD(T)
method,
outperforms
all
tested
multireference
methods:
CASPT2,
MRCI+Q,
CASPT2/CC
CASPT2+δMRCI.
Contrary
claims
literature,
use
Kohn–Sham
instead
Hartree–Fock
orbitals
determinant
consistently
improve
energetics.
best
performing
DFT
double-hybrids
(PWPB95-D3(BJ),
B2PLYP-D3(BJ))
MAEs
below
3
errors
within
6
kcal/mol,
whereas
traditionally
recommended
spin
states
(e.g.,
B3LYP*-D3(BJ)
TPSSh-D3(BJ))
perform
much
worse
5–7
beyond
10
kcal/mol.
results
this
work
proper
characterize
systems
catalysis
(bio)inorganic
may
also
stimulate
developments
quantum-chemical
machine
learning
approaches.
Язык: Английский
Spin–State Energetics for Hydride and Helium Models of Transition Metal Complexes: A Benchmark Study of Wave Function Quantum Chemistry Methods
Опубликована: Авг. 16, 2024
Accurate
determination
of
spin–state
energetics
in
first-row
transition
metal
(TM)
complexes
is
recognized
as
a
challenging
problem
computational
quantum
chemistry
because
different
methods
often
yield
divergent
predictions
and
credible
reference
data
are
scarce.
Trying
to
provide
way
towards
unambiguously
accurate
values
from
high-level
wave
function
computation,
benchmark
set
small
TM
with
hydrides
(H^–)
or
helium
atoms
σ-donor
ligands
presented.
These
models
have
analogous
electronic
structures
realistic
their
feature
comparable
method-
dependence,
but
size
enables
application
more
than
applicable
complexes.
The
extrapolated
full
configuration
interaction
(exFCI)
results
obtained
for
selected
splittings
the
hydride/helium
used
benchmarking
various
methods,
including
second-
third-order
perturbation
theory
multireference
CI,
coupled
cluster
up
approximate
quadruples.
It
demonstrated
that
exFCI
can
be
reproduced
satisfactorily
both
single-reference
among
which
NEVPT2
CCSDT(Q)_Λ
perform
best,
yielding
deviations
uncertainties
smaller
2
kcal/mol.
CCSD(T)
method
yields
errors
ca.
3
kcal/mol
smaller,
one
exception
where
CCSD(T)’s
error
greater
6
presumably
due
pronounced
character.
CASPT2,
CASPT3,
CASPT2/CC
shown
not
outperform
consistently.
present
study,
addition
presenting
novel
problem,
establishes
useful
systems
further
investigations
correlated
structure
methods.
Язык: Английский