Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Molecular Orbital Theory I02:35

Molecular Orbital Theory I

49.0K
Overview of Molecular Orbital Theory
49.0K
MO Theory and Covalent Bonding02:40

MO Theory and Covalent Bonding

14.7K
The molecular orbital theory describes the distribution of electrons in molecules in a manner similar to the distribution of electrons in atomic orbitals. The region of space in which a valence electron in a molecule is likely to be found is called a molecular orbital. Mathematically, the linear combination of atomic orbitals (LCAO) generates molecular orbitals. Combinations of in-phase atomic orbital wave functions result in regions with a high probability of electron density, while...
14.7K
Molecular Orbital Theory II03:51

Molecular Orbital Theory II

28.3K
Molecular Orbital Energy Diagrams
28.3K
The Uncertainty Principle04:08

The Uncertainty Principle

34.4K
Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that there is a fundamental limit to how accurately one can measure both a particle’s position and its momentum simultaneously. The more accurate the measurement of the momentum of a particle is known, the less accurate the position at that time is known and vice versa. This is what is now called the Heisenberg uncertainty principle. He...
34.4K
Chemical Shift: Internal References and Solvent Effects01:17

Chemical Shift: Internal References and Solvent Effects

1.6K
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
1.6K
¹H NMR: Complex Splitting01:13

¹H NMR: Complex Splitting

2.1K
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
2.1K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Computer-aided detection thresholds can guide repeat rapid molecular testing in TB screening.

IJTLD open·2026
Same author

Black Hole Spectroscopy and Tests of General Relativity with GW250114.

Physical review letters·2026
Same author

GW250114: Testing Hawking's Area Law and the Kerr Nature of Black Holes.

Physical review letters·2025
Same author

High-throughput formulation of reproducible 3D cancer microenvironments for drug testing in myeloid leukemia.

Biofabrication·2024
Same author

Prevalence of intellectual disability among adults born in the 1980s and 1990s in the United States.

Journal of intellectual disability research : JIDR·2024
Same author

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run.

Physical review letters·2022

Related Experiment Video

Updated: Mar 18, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
12:11

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

8.8K

Molecular Applications of a Size-Consistent State-Specific Multireference Perturbation Theory with Relaxed

U Sinha Mahapatra1, B Datta1, D Mukherjee1

  • 1Department of Physical Chemistry, Indian Association for the Cultivation of Science, Calcutta 700-032, India.

The Journal of Physical Chemistry. A
|July 8, 2016
PubMed
Summary

This study introduces new perturbative methods for multireference state-specific coupled-cluster (SS-MRCC) calculations, effectively handling intruders in potential energy surfaces. These advanced techniques offer smooth performance where other methods fail.

More Related Videos

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
08:04

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

9.0K
Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
05:51

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method

Published on: July 19, 2019

6.7K

Related Experiment Videos

Last Updated: Mar 18, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
12:11

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry

Published on: April 8, 2020

8.8K
Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
08:04

Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids

Published on: May 27, 2020

9.0K
Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method
05:51

Isotopic Effect in Double Proton Transfer Process of Porphycene Investigated by Enhanced QM/MM Method

Published on: July 19, 2019

6.7K

Area of Science:

  • Quantum Chemistry
  • Computational Chemistry
  • Theoretical Chemistry

Background:

  • Existing multireference coupled-cluster methods face challenges with intruders, particularly in potential energy surface (PES) calculations.
  • Intruders can lead to inaccuracies and poor convergence in theoretical chemistry calculations.
  • The need for robust methods that maintain size-extensivity and size-consistency is critical.

Purpose of the Study:

  • To develop and evaluate Rayleigh-Schrödinger (RS) and Brillouin-Wigner (BW) perturbative versions of a novel state-specific multireference coupled-cluster (SS-MRCC) formalism.
  • To assess the efficacy of these new methods in handling systems with intruder states.
  • To compare the performance of the developed SS-MRCC perturbative methods against traditional approaches.

Main Methods:

  • Development of second-order energy calculations using RS and BW perturbation theories within the SS-MRCC framework.
  • Utilized a sum-of-exponentials Ansatz for the wave operator, resolving redundancy via sufficiency conditions.
  • Employed a suitable partitioning of the Hamiltonian to define the unperturbed Hamiltonian.

Main Results:

  • The developed SS-MRCC perturbative formalisms demonstrated smooth performance in regions with intruder states.
  • These methods successfully bypassed intruder problems, providing reliable results for potential energy surfaces.
  • In contrast, effective Hamiltonian-based multireference MBPT methods showed poor performance near intruders.

Conclusions:

  • The novel state-specific perturbative coupled-cluster methods are effective in circumventing intruder state issues in quantum chemical calculations.
  • These formalisms offer a significant improvement for studying molecules with multireference character and complex potential energy landscapes.
  • The developed methods provide a robust alternative for challenging electronic structure problems.