1. IterativeDiagonalization in the MulticonfigurationalTime-Dependent Hartree Approach: Ro-vibrational Eigenstates.
- Author
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Wodraszka, Robert and Manthe, Uwe
- Subjects
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HARTREE-Fock approximation , *VIBRATIONAL spectra , *ANGULAR momentum (Mechanics) , *WAVE packets , *WIGNER rotation matrix , *ITERATIVE methods (Mathematics) , *HAMILTONIAN systems , *POTENTIAL energy surfaces - Abstract
A schemeto efficiently calculate ro-vibrational (J> 0)eigenstates within the framework of the multiconfigurational time-dependentHartree (MCTDH) approach is introduced. It employsa basis of MCTDH wave packets which is generated in the calculationof vibrational (J= 0) eigenstates via existing MCTDH-basediterative diagonalization approaches. The subsequent ro-vibrationalcalculations for total angular momenta J> 0 usedirect products of these wave packets and the Wigner rotation matrices.In this ro-vibrational basis, the Hamiltonian matrix can be computedand diagonalized with minor numerical effort for any value of J. Accurate ro-vibrational states are obtained if the numberof iterations in the J= 0 calculations and the basisset sizes in the MCTDH wave function representation are converged.Test calculations studying CH2D show that ro-vibrationaleigenstates for moderately large Jcan be convergedwithin wavenumber accuracy with the same MCTDH basis sets and onlyslightly increased iteration counts compared to purely vibrational(J= 0) calculations. If large J’s are considered or very high accuracies are required, thenumber of iterations required to obtain convergence increases significantly.Comparing the theoretical results with experimental data for the out-of-planebend, symmetric stretch, and antisymmetric stretch fundamentals, theaccuracy of the ab initio potential energy surface employed is investigated. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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