Ab initio R-matrix/multi-channel quantum defect theory applied to molecular core excitation and ionization

2005 ◽  
Vol 144-147 ◽  
pp. 1223-1226 ◽  
Author(s):  
Miyabi Hiyama ◽  
Nobuhiro Kosugi
Keyword(s):  
Ab Initio ◽  
Quantum Defect ◽  
Core Excitation ◽  
R Matrix ◽  
Molecular Core ◽  
Quantum Defect Theory

AB INITIO R-MATRIX/MULTI-CHANNEL QUANTUM DEFECT THEORY APPROACH TO STUDY MOLECULAR CORE EXCITATION AND IONIZATION: GSCF4R

2005 ◽  
Vol 04 (01) ◽  
pp. 35-47 ◽  
Author(s):  
MIYABI HIYAMA ◽  
NOBUHIRO KOSUGI
Keyword(s):  
Ab Initio ◽  
Quantum Defect ◽  
Theory Approach ◽  
Core Excitation ◽  
Close Coupling ◽  
R Matrix ◽  
Continuum States ◽  
Molecular Core ◽  
Quantum Defect Theory ◽  
Correlation Term

The ab initio program package named GSCF4R, which is based on the polyatomic R-matrix/MQDT (multi-channel quantum defect theory), has been developed using Gaussian type basis functions for the bound and continuum states to analyze the near edge feature of molecular inner shell excitations. The GSCF4R code is constructed by improvement and extension of the ordinal static exchange (STEX) approach. The R-matrix approach used in GSCF4R is beyond multi-channel multi-reference extensions of STEX, since it is based on the close coupling method augmented with the correlation term solved in the inner part of the R-matrix sphere. Simplification of the input data in GSCF4R has demonstrated that the R-matrix/MQDT method could be widely used in analysis of the molecular inner shell excitation and ionization. The quantum defects of the Rydberg states converging to the lowest valence ionized state NO +(1∑+) and the lowest N1 s ionized state N ⋆ O +(3Π) have been calculated.

Quantum defect theory of dipole-mixed Rydberg states in CaF

2001 ◽  
Vol 79 (2-3) ◽  
pp. 287-298 ◽  
Author(s):  
Ch. Jungen ◽  
A L Roche
Keyword(s):  
Preceding Paper ◽  
Chem Phys ◽  
Quantum Defect ◽  
Quadrupole Moments ◽  
R Matrix ◽  
Fitting Procedure ◽  
Quantum Numbers ◽  
Effective Principal ◽  
Vibration Rotation ◽  
Quantum Defect Theory

491 rovibronic levels of electronically highly excited CaF have been analyzed using multichannel quantum defect theory (MQDT). These levels, observed in the experiments described in the preceding paper, correspond to effective principal quantum numbers ν [Formula: see text] 12–18, partial wave components l = 0–3, and vibration–rotation quantum numbers ν = 1 and N = 0–14. A set of nondiagonal quantum defect matrices has been extracted from the experimental data by means of a global least-squares-fitting procedure, and is found to agree reasonably well with the theoretical quantum defect matrices calculated previously by Arif et al. J. Chem. Phys. 106, 4102 (1997) where the variational R-matrix method was used. The MQDT analysis accounts for rotational–electronic nonadiabatic decoupling of the Rydberg electron from the rotating dipolar core as well as for strong l-mixing induced by the latter. The quantum defects determined for l = 3 yield approximate values for the core dipole and quadrupole moments. PACS Nos.: 33.10Lb, 34.50Gb, 34.60+z

Multichannel quantum defect theory treatment of triplet gerade and ungerade d-symmetry levelsof H2 and its isotopomers

2001 ◽  
Vol 79 (2-3) ◽  
pp. 561-588 ◽  
Author(s):  
S C Ross ◽  
Ch. Jungen ◽  
A Matzkin
Keyword(s):  
Potential Energy ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Internuclear Distance ◽  
Electronic Transition ◽  
Hydrogen Molecule ◽  
Quantum Defect ◽  
Companion Article ◽  
Quantum Defect Theory ◽  
Better Than

This work presents a systematic multichannel quantum defect theory (MQDT) analysis of the triplet d-symmetry levels of the hydrogen molecule. First, a new compilation of the best available experimental term values for these levels was prepared. Second, R-dependent quantum defect matrices for the 3Πu, 3Πg, and 3Δg states of H2 were obtained from ab initio potential-energy curves and used in an ab initio MQDT calculation of all known triplet d-symmetry rovibronic levels of H2, HD, and D2. For a few of these levels previous ab initio calculations have been reported. The agreement currently obtained is generally significantly better than that in previous work. Finally, the quantum defect matrices are used to calculate the electronic transition moments 3Πu [Formula: see text] 3Πg, 3Δg as functions of energy and internuclear distance, R, for application in a companion article. PACS Nos: 31.15Ar, 33.20Wr, 34.10+x, 34.80Kw

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