Application of generalized quantum defect theory to van der Waals complex bound state calculations

Fourré, Isabelle; Raoult, Maurice

doi:10.1063/1.468066

Cited by 14 publications

(22 citation statements)

References 39 publications

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“…For the continuum or quasidiscrete levels ͑positive energy with respect to the adiabatic dissociation limit͒, a one-dimension close-coupling approach was used in the potential matrix U j, j Ј (R) set by taking the matrix elements of each PES V(R,) between the rotational wave functions Y j () of the NO diatom. 40 For the intensity calculations of the excitation spectra, the electronic transition moment was set to 1, so that only Franck-Condon overlap over the R and coordinates is considered. Further approximations were also made in this calculation, i.e., no hot band was considered and the spin structure of the upper state was ignored, so that we did not try to fit the fine structure observed in the C -X spectrum.…”

Section: Calculation Of the Franck-condon Transitions For The A -Xmentioning

confidence: 99%

A, C, and D electronic states of the Ar–NO van der Waals molecule revisited: Experiment and theory

Shafizadeh

Bréchignac

Dyndgaard

et al. 1998

The Journal of Chemical Physics

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The A -X transition of ArNO has been reinvestigated by laser induced fluorescence ͑LIF͒ both in the bound-free and bound-bound region. The discrete part of the spectrum is at least two orders of magnitude weaker than the continuum part, indicative of a large change in geometry from the ground state. This very different configuration, both from the ground state and from the C and D states, can only be explained by strong interactions, induced by the perturbing argon atom, between the excited states of the van der Waals complex converging to the 3s,A, 3p,C, and 3 p,D Rydberg states of NO. In order to quantitatively understand the observed structure of the A -X, C -X, and D -X excitation spectra, a global theoretical approach is proposed, based on ab initio calculations of the potential energy surfaces in the planar AЈ and AЉ symmetries, including a configuration interaction between the states of same symmetry. Small adjustments of the diabatic energy surfaces lead to a satisfactory agreement between the observed and calculated spectra. In contrast to the ground state, the Renner-Teller splitting of the 3 p,C state into two AЈ and AЉ components is very large, of the order of 4000 cm Ϫ1 . This effect is complicated by further mixing between the states of AЈ symmetry induced by the argon atom. The A state is anisotropic and weakly bound with a small potential well at the linear configuration ͑the argon atom being on the side of the oxygen͒. The C(AЉ) and the bound electronic component of the strongly mixed C ϩD(AЈ) states exhibit a vibrational structure close to that of the ion and, consequently, present some Rydberg character even if the Coulomb field central symmetry (s-p) is broken by the perturbing argon atom.

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Section: Calculation Of the Franck-condon Transitions For The A -Xmentioning

confidence: 99%

A, C, and D electronic states of the Ar–NO van der Waals molecule revisited: Experiment and theory

Shafizadeh

Bréchignac

Dyndgaard

et al. 1998

The Journal of Chemical Physics

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“…In this case the open-and closed-channel blocks of Y are uncoupled, so thatȲ ≈ Y oo , and the resonances appear through the Y oo term in Eq. (21) rather than through tan ν + Y cc [58]. However, if r match is small enough, the resonance features are shifted to high energies, out of the region of interest.…”

Section: Choice Of R Match and Reference Potentialmentioning

confidence: 99%

Multichannel quantum defect theory for cold molecular collisions

et al. 2011

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'Multichannel quantum defect theory for cold molecular collisions. ', Physical review A., 84 (4). 042703.Further information on publisher's website: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Multichannel quantum defect theory (MQDT) is shown to be capable of producing quantitatively accurate results for low-energy atom-molecule scattering calculations. With a suitable choice of reference potential and short-range matching distance, it is possible to define a matrix that encapsulates the short-range collision dynamics and is only weakly dependent on energy and magnetic field. Once this has been produced, calculations at additional energies and fields can be performed at a computational cost that is proportional to the number of channels N and not to N 3 . MQDT thus provides a promising method for carrying out low-energy molecular scattering calculations on systems where full exploration of the energy dependence and the field dependence is currently impractical.

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“…which allows defining the classical time delay [40,41,42]: where the summation over k concerns complex eigenvalues with real part larger than the energy of the P 1/2 asymptote. From Fig.2c, we clearly identify resonances by their larger time delay, compared to the continuum states.…”

Section: The Mfgh Methods With Optical Potentialmentioning

confidence: 99%

Optimization of generalized multichannel quantum defect reference functions for Feshbach resonance characterization

Osseni¹,

Dulieu²,

Raoult³

2009

J. Phys. B: At. Mol. Opt. Phys.

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This work stresses the importance of the choice of the set of reference functions in the Generalized Multichannel Quantum Defect Theory to analyze the location and the width of Feshbach resonance occurring in collisional cross-sections. This is illustrated on the photoassociation of cold rubidium atom pairs, which is also modeled using the Mapped Fourier Grid Hamiltonian method combined with an optical potential. The specificity of the present example lies in a high density of quasi-bound states (closed channel) interacting with a dissociation continuum (open channel). We demonstrate that the optimization of the reference functions leads to quantum defects with a weak energy dependence across the relevant energy threshold. The main result of our paper is that the agreement between the both theoretical approaches is achieved only if optimized reference functions are used.

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Application of generalized quantum defect theory to van der Waals complex bound state calculations

Cited by 14 publications

References 39 publications

A, C, and D electronic states of the Ar–NO van der Waals molecule revisited: Experiment and theory

A, C, and D electronic states of the Ar–NO van der Waals molecule revisited: Experiment and theory

Multichannel quantum defect theory for cold molecular collisions

Optimization of generalized multichannel quantum defect reference functions for Feshbach resonance characterization

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