Application of<i>Z</i>-dependent perturbation theory to autoionizing states of heliumlike atoms: Feshbach projection method

We investigate, at a density functional level, the electric characteristics of 18 complexes of cobalt phthalocyanine (CoPc) and cobalt tetraaminephthalocyanine (CoTAPc) adsorbed on graphene functionalized with CO 2 À or CO moieties. Three models of graphene molecules are used, pristine, defect, and vacancy, leading to 12 complexes with CO 2 À functionalized graphene and 6 complexes with functionalized CO graphene. The molecular structures of the optimized complexes feature covalent adsorption CoÀO lengths of ∼1.9À2.1 Å and CÀN lengths of ∼1.4 Å in parallel, perpendicular, and coplanar structures of graphene with phthalocyanine. All these conformations have a direct effect on the electronic characteristics of the complexes. Binding energies calculated for the interaction between functionalized graphene and phthalocyanine show that structures with defects and vacancies have lower energies than pristine graphene. In particular, we found that complexes having a graphene-CO linked to phthalocyanine by an amide bond are of highest stability (by ∼130 kcal/mol) and the formation of complexes with CO 2 À functionalized graphenes takes place preferably when involved with CoTAPc (by ∼20 kcal/mol). Frontier molecular orbitals (HOMO and LUMO) suggest that several of these complexes behave as charge transfer compounds with phthalocyanine as an electron donor and graphene as an electron acceptor, thus these complexes could behave as sensors because of the absorption properties of phthalocyanine in the UVÀvis region. The calculated currentÀvoltage characteristics show that electron transfer is preferably favored in complexes with parallel structure and with pristine graphene CO 2 À functionalization (∼7 μA) when both conjugates, graphene and phthalocyanine, face each other. The latter implies the transfer of charge through a πÀπ setting. However, the presence of defects and vacancies, for this face to face structure, shows lower electron transfer, having G-Def and G-Vac similar values of electron transfer. The conduction is very low for complexes with high stability (usually the coplanar structures) and with charge transfer features, i.e., those in which the HOMO and LUMO are in separated parts of the complex (usually the perpendicular and the coplanar structures). This study shows that cobalt phthalocyanine conducts electrical current toward graphene through a covalently attached CO 2 À to the graphene.

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“…82 The transmission probability, T, and the total density of states, D, of the molecular junction are …”

Section: Methodsmentioning

confidence: 99%

Electrical Characteristics of Cobalt Phthalocyanine Complexes Adsorbed on Graphene

Cárdenas-Jirón

León-Plata²,

Cortés‐Arriagada

et al. 2011

J. Phys. Chem. C

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“…Once the opti, mized value for 0 is obtained, we can examine the convergence behaviors for the resonance parameters for different expansion lengths. 1 2 8 1 7 0 R y ± l × 1 0 -6 R y and ~---0.000301Ry [27] Feshbach projection formalism with Hylleraas functions and full scattering non-resonant continuum [30] saddle-point complex-rotation [29] r L2.technique [32] g algebraic variational close coupling [24] nine-channel many-body perturbation theory [25] variational R-matrix calculation [26] J L2-technique with Sturmian functions [33] k Feshbach projection Z-perturbation [31] i L2_technique with B-spline basis [34] m Feshbach saddle point technique [28] n L2.technique, non-variational CI with B-spline basis [35] large amount. It should also be mentioned that the present calculation is not a bound calculation.…”

Section: Wave Functions and Calculationsmentioning

confidence: 99%

Doubly excited1 P 0 resonances in He

1991

Z Phys D - Atoms, Molecules and Clusters

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Doubly excited 1p0 autoionizating states in He below the n = 2 threshold of He ÷ ions are calculated by use of a method of complex-coordinate rotation. Hylleraas type wave functions are used to calculate resonance parameters for intrashell states (the two electrons occupy the same shell), and products of Slater-orbitals are used for intershell states (the two electrons occupy different shells). A total of 15 resonances below the n=2He + thresholds are reported in this work. This includes six members in the 2snp+ (2 ___< n =< 7) series, five members in the 2snp_ (3_

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“…The 1/Z expansion method has advantage of yielding f or S values for the entire isoelectronic sequence by just carrying out a simple analysis. The Z-dependent perturbation theory has also been used successfully for the study of autoionising states of two-electron ions [8], and in the quantum-defect studies of systematic trends of f values [9].…”

Section: Introductionmentioning

confidence: 99%

Systematic trends in the radial matrix elements of E1 transitions in Li, F, Na and Cu isoelectronic sequences

Bharadvaja

Baluja

1996

Z Phys D - Atoms, Molecules and Clusters

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Scaled radial matrix elements Z for dipole allowed transitions in Li, F, Na and Cu isoelectronic sequences have been fitted in the form Z "A# B/(Z!C)#D(Z!Ze). The constants A, B, C, D are determined using a non-linear least square fit method; Z is the nuclear charge of a particular ion and Ze is the number of electrons in the core. It has been shown that the fitted value A for various transitions studied is in good agreement with the non-relativistic ab-initio value A of Z in the limit ZP-. The last term of the above expansion accounts for the relativistic effects for heavier ions which are significant for Z'26. The coefficient D is proportional to where is a fine structure constant and is a measure of relativistic contribution to allowed dipole radial matrix elements.

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Application ofZ-dependent perturbation theory to autoionizing states of heliumlike atoms: Feshbach projection method

Cited by 32 publications

References 49 publications

Electrical Characteristics of Cobalt Phthalocyanine Complexes Adsorbed on Graphene

Electrical Characteristics of Cobalt Phthalocyanine Complexes Adsorbed on Graphene

Doubly excited1 P 0 resonances in He

Systematic trends in the radial matrix elements of E1 transitions in Li, F, Na and Cu isoelectronic sequences

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