Internally contracted multiconfiguration-reference configuration interaction calculations for excited states

@article{Knowles1992InternallyCM,
  title={Internally contracted multiconfiguration-reference configuration interaction calculations for excited states},
  author={Peter J. Knowles and Hans-Joachim Werner},
  journal={Theoretica chimica acta},
  year={1992},
  volume={84},
  pages={95-103}
}
SummaryThe calculation of electronically excited states with the internally contracted multiconfiguration-reference configuration interaction (CMRCI) method is discussed. A straightforward method, in which contracted functions for all states are included in the basis, is shown to be very accurate and stable even in cases of narrow avoided crossings. However, the expense strongly increases with the number of states. A new method is proposed, which employs different contracted basis sets for each… Expand
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References

SHOWING 1-10 OF 17 REFERENCES
An efficient internally contracted multiconfiguration–reference configuration interaction method
A new internally contracted direct multiconfiguration–reference configuration interaction (MRCI) method is described which allows the use of much larger reference spaces than any previous MRCIExpand
A comparison of variational and non-variational internally contracted multiconfiguration-reference configuration interaction calculations
SummaryThe internally contracted multiconfiguration-reference configuration interaction (CMRCI) method and several non-variational variants of this method (averaged coupled pair approximation (ACPF),Expand
The CASSCF state interaction method
Abstract A method is described to calculate the matrix elements of one- and two-electron operators for CASSCF wavefunctions employing individually optimized orbitals. The computation procedure isExpand
The self‐consistent electron pairs method for multiconfiguration reference state functions
An efficient direct CI method which includes all singly and doubly substituted configurations with respect to an arbitrary multiconfiguration (MCSCF) reference function is described. TheExpand
Accurate multireference configuration interaction calculations of the potential energy function and the dissociation energy of N2
The potential energy function of the N2 molecule is calculated using the internally contracted multireference CI method (CMRCI) and complete active space SCF (CASSCF) reference wave functions. A fullExpand
Direct configuration interaction with a reference state composed of many reference configurations
The configuration interaction method where a single reference state is composed of a linear combination of reference configurations is analyzed in detail. In this method single and doubleExpand
An efficient method for the evaluation of coupling coefficients in configuration interaction calculations
Abstract A new method for evaluating one-particle coupling coefficients in a general configuration interaction calculation is presented. Through repeated application and use of resolutions of theExpand
Individualized configuration selection in CI calculations with subsequent energy extrapolation
A configuration selection method for CI calculations is discussed and applied in which the energy lowering produced in a secular equation by the addition of a given test species to a series ofExpand
Advanced theories and computational approaches to the electronic structure of molecules
Chemical Computations on an Attached Processor: Quantum Chemistry Applications.- Considerations in Vectorizing the CI Procedure.- The Method of Self Consistent Electron Pairs. A Matrix OrientedExpand
The shape‐driven graphical unitary group approach to the electron correlation problem. Application to the ethylene molecule
A new method for the approximate solution of Schrodinger’s equation for many electron molecular systems is outlined. The new method is based on the unitary group approach (UGA) and exploits inExpand
...
1
2
...