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Jiang J, Barnum TJ, Coy SL, Field RW. Analysis of vibrational autoionization of CaF Rydberg states. J Chem Phys 2019; 150:154305. [PMID: 31005082 DOI: 10.1063/1.5091526] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report calculations of vibrational autoionization rates of CaF Rydberg states, based on the results of a global multi-channel quantum defect theory (MQDT) fit. Our goal is to use intuitive physical models to interpret and extend the results from the MQDT calculations and, in particular, to characterize the physical mechanisms for the interaction between the Rydberg electron and the ion-core. The calculations indicate that, among the six strongly l-mixed core-penetrating (CP) Rydberg series of CaF, the n.36 p^Π Rydberg series has the fastest Δv = 1 vibrational autoionization rate, which is at least four times larger than that for the other CP Rydberg series, in agreement with experimental results. We first demonstrate that the rotational level dependence of the vibrational autoionization rate of the n.36 p^Π series is satisfactorily explained by l-uncoupling interactions, which differ for the positive and negative Kronig symmetry levels. Next, we interpret the relative vibrational autoionization rates of all six CP Rydberg series in the context of a valence-precursor (VP) model. The VP model is a consequence of Mulliken's rule, which states that the innermost lobe of the Rydberg wavefunction remains invariant in both the nodal position and shape for members of the same Rydberg series. The electronic properties of the six VP states, which are the terminus states (lowest-n) of each of the six CP Rydberg series, are further characterized in terms of a ligand-field model, providing insight into the intimate relationship between the Rydberg electron density in the ion-core region and the vibrational autoionization rate.
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Affiliation(s)
- Jun Jiang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Timothy J Barnum
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Stephen L Coy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Coy SL, Grimes DD, Zhou Y, Field RW, Wong BM. Electric potential invariants and ions-in-molecules effective potentials for molecular Rydberg states. J Chem Phys 2016; 145:234301. [DOI: 10.1063/1.4968228] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Stephen L. Coy
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachussetts 02139, USA
| | - David D. Grimes
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachussetts 02139, USA
| | - Yan Zhou
- JILA, University of Colorado Boulder, 440 University Ave., Boulder, Colorado 80302, USA
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachussetts 02139, USA
| | - Bryan M. Wong
- Department of Chemical and Environmental Engineering and Materials Science & Engineering Program, University of California, Riverside, California 92521, USA
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Abstract
Theoretical study of electron impact scattering by disilane molecule is reported in this article.
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Affiliation(s)
- Dhanoj Gupta
- Department of Applied Physics
- Indian School of Mines
- Dhanbad, India
| | - Rahla Naghma
- Department of Applied Physics
- Indian School of Mines
- Dhanbad, India
| | - Biplab Goswami
- Department of Applied Physics
- Indian School of Mines
- Dhanbad, India
| | - Bobby Antony
- Department of Applied Physics
- Indian School of Mines
- Dhanbad, India
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Kay JJ, Coy SL, Wong BM, Jungen C, Field RW. A quantum defect model for the s, p, d, and f Rydberg series of CaF. J Chem Phys 2011; 134:114313. [DOI: 10.1063/1.3565967] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Jeffrey J Kay
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Sheridan PM, Wang JG, Dick MJ, Bernath PF. Optical−Optical Double Resonance Spectroscopy of the C2Π−A2Π and D2Σ+−A2Π Transitions of SrF. J Phys Chem A 2009; 113:13383-9. [DOI: 10.1021/jp9020855] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Phillip M. Sheridan
- Department of Chemistry and Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Jin-Guo Wang
- Department of Chemistry and Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Michael J. Dick
- Department of Chemistry and Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Peter F. Bernath
- Department of Chemistry and Department of Physics, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Petrović VS, Kay JJ, Coy SL, Field RW. The Stark effect in Rydberg states of a highly polar diatomic molecule: CaF. J Chem Phys 2009; 131:064301. [DOI: 10.1063/1.3179942] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Kay JJ, Coy SL, Petrović VS, Wong BM, Field RW. Separation of long-range and short-range interactions in Rydberg states of diatomic molecules. J Chem Phys 2008; 128:194301. [DOI: 10.1063/1.2907858] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Altunata SN, Coy SL, Field RW. Broad shape resonance effects in CaF Rydberg states. J Chem Phys 2006; 124:194302. [PMID: 16729809 DOI: 10.1063/1.2192518] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Results of ab initio R-matrix calculations [S. N. Altunata et al., J. Chem. Phys. 123, 084319 (2005)] indicate the presence of a broad shape resonance in electron-CaF(+) scattering for the (2)Sigma(+) electronic symmetry near the ionization threshold. The properties of this shape resonance are analyzed using the adiabatic partial-wave expansion of the scattered electron wave function introduced by Le Dourneuf et al. [J. Phys. B 15, L685 (1982)]. The qualitative aspects of the shape resonance are explained by an adiabatic approximation on the electronic motion. Mulliken's rule for the structure of the Rydberg state wave functions [R. S. Mulliken, J. Am. Chem. Soc. 86, 3183 (1964)] specifies that, except for an (n*)(-32) amplitude scale factor, every excited state wave function within one Rydberg series is built on an innermost lobe that remains invariant in shape and nodal position as a function of the excitation energy. Mulliken's rule implies a weak energy dependence of the quantum defects for an unperturbed molecular Rydberg series, which is given by the Rydberg-Ritz formula. This zero-order picture is violated by a single (2)Sigma(+) CaF Rydberg series at all Rydberg state energies (n*=5-->infinity, more so with increasing n*) below the ionization threshold, under the broad width of the shape resonance. Such a violation is diagnostic of a global "scarring" of the Rydberg spectrum, which is distinct from the more familiar local level perturbations.
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Affiliation(s)
- Serhan N Altunata
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Wong BM, Altunata SN, Field RW. Analytical calculations of molecular integrals for multielectron R-matrix methods. J Chem Phys 2006; 124:14106. [PMID: 16409023 DOI: 10.1063/1.2137320] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Closed-form analytical expressions for one- and two-electron integrals between Cartesian Gaussians over a finite spherical region of space are developed for use in ab initio molecular scattering calculations. In contrast with some previous approaches, the necessary integrals are formulated solely in terms of finite summations involving standard functions. The molecular integrals evaluated over the finite region of space are computed by subtracting the contributions outside the region from the integrals over all space. The latter integrals can be efficiently and accurately obtained from existing bound-state algorithms. Our approach incorporates molecular scattering calculations into current quantum chemistry programs and facilitates the unification of bound- and continuum-state calculations for both diatomic and polyatomic molecules. Multidimensional Monte Carlo numerical integrations validate the high accuracy of our closed form results for the two-electron integrals.
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Affiliation(s)
- Bryan M Wong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Altunata SN, Coy SL, Field RW. Properties of nearly one-electron molecules. I. An iterative Green function approach to calculating the reaction matrix. J Chem Phys 2005; 123:084318. [PMID: 16164302 DOI: 10.1063/1.2005017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An ab initio R-matrix method for determining the molecular reaction matrix of scattering theory is introduced. The method makes use of a principal-value Green function to compute the collision channel wave functions for the scattered electron, in combination with the Kohn variational scheme for the evaluation of R-matrix eigenvalues on a spherical boundary surface at short range. This technique permits the size of the bounded volume in the variational calculation to be reduced, making the computations fast and efficient. The reaction matrix is determined in a form that minimizes its energy dependence. Thus the procedure does not require modification or an increase in the computational effort to study the electronic structure and dynamics in Rydberg molecules with extremely polar ion cores. The analysis is specialized to examine the bound-state and free-electron scattering properties of nearly one-electron molecular systems, which are characterized by a Rydberg/scattering electron incident on a closed-shell ion core. However, it is shown that the treatment is compatible with all-electron/ab initio representations of open-shell and nonlinear polyatomic ion cores, emphasizing its generality. The introduced approach is used to calculate the electronic spectrum of the calcium monofluoride molecule, which has the extremely polar (Ca+2F-)+e- closed-shell ion-core configuration. The calculation utilizes an effective single-electron potential determined by M. Arif, C. Jungen, and A. L. Roche [J. Chem. Phys. 106, 4102 (1997)] previously. Close agreement with experimental data is obtained. The results demonstrate the practical utility of this method as a viable alternative to the standard variational approaches.
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Affiliation(s)
- Serhan N Altunata
- Department of Chemistry and G.R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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