Basis set limitations on the ab initio calculation of stopping cross-sections via generalized oscillator strengths

Nobel, J. A.; Trickey, S. B.; Sabin, John R.; Oddershede, Jens

doi:10.1016/j.chemphys.2004.05.027

Cited by 7 publications

(5 citation statements)

References 22 publications

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“…I, there are other areas in computational physics and chemistry where considering larger basis sets does not necessarily lead to better results. 62 In principle this is true of the calculation of any nonvariational property such as, e.g., response properties or transmission functions, for which virtual MOs play a significant role. Apart from sum rules, there is often no general criterion as to how to estimate the error introduced by changing the size of the basis set.…”

Section: Discussion: Ghost Transmission As a Biased Description Omentioning

confidence: 99%

“…This may be related to other accounts of situations where employing a larger basis set does not necessarily lead to more accurate results, in particular when calculating nonvariational properties, but also for dimerization energies. 62 This manuscript is organized as follows. First, the implementation of the Landauer approximation employed here is briefly outlined, and the concept of ghost transmission is introduced.…”

Section: Introductionmentioning

confidence: 99%

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Ghost transmission: How large basis sets can make electron transport calculations worse

Herrmann

Solomon

Subotnik

et al. 2010

The Journal of Chemical Physics

102

123

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The Landauer approach has proven to be an invaluable tool for calculating the electron transport properties of single molecules, especially when combined with a nonequilibrium Green's function approach and Kohn-Sham density functional theory. However, when using large nonorthogonal atom-centered basis sets, such as those common in quantum chemistry, one can find erroneous results if the Landauer approach is applied blindly. In fact, basis sets of triple-zeta quality or higher sometimes result in an artificially high transmission and possibly even qualitatively wrong conclusions regarding chemical trends. In these cases, transport persists when molecular atoms are replaced by basis functions alone ("ghost atoms"). The occurrence of such ghost transmission is correlated with low-energy virtual molecular orbitals of the central subsystem and may be interpreted as a biased and thus inaccurate description of vacuum transmission. An approximate practical correction scheme is to calculate the ghost transmission and subtract it from the full transmission. As a further consequence of this study, it is recommended that sensitive molecules be used for parameter studies, in particular those whose transmission functions show antiresonance features such as benzene-based systems connected to the electrodes in meta positions and other low-conducting systems such as alkanes and silanes.

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Section: Discussion: Ghost Transmission As a Biased Description Omentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ghost transmission: How large basis sets can make electron transport calculations worse

Herrmann

Solomon

Subotnik

et al. 2010

The Journal of Chemical Physics

102

123

View full text Add to dashboard Cite

show abstract

“…The choice of the proper size of basis set is of significance for the study on the electronic coupling of ET. Employing larger basis sets does not necessarily produce better results, not only for electronic coupling 38,39,42 , but also for response properties 105 and transmission functions 106 . This is explained as follows: (1) HF calculations for anion systems with the diffuse-function basis sets produce the lowest lying virtual orbitals corresponding to the "discrete" continuum states.…”

Section: All Excitations 0 or 1 Excitationmentioning

confidence: 98%

Pathway analysis of super-exchange electronic couplings in electron transfer reactions using a multi-configuration self-consistent field method

Nishioka

Ando

2011

Phys. Chem. Chem. Phys.

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We present a novel pathway analysis of super-exchange electronic couplings in electron transfer reactions using localized molecular orbitals from multi-configuration self-consistent field (MCSCF) calculations. In our analysis, the electronic coupling and the tunneling pathways can be calculated in terms of the configuration interaction (CI) Hamiltonian matrix obtained from the localized MCSCF wave function. Making use of the occupation restricted multiple active spaces (ORMAS) method can effectively produce the donor, acceptor, and intermediate configuration state functions (CSFs) and CIs among these CSFs. In order to express the electronic coupling as a sum of individual tunneling pathways contributions, we employed two perturbative methods: Löwdin projection-iteration method and higher-order super-exchange method. We applied them to anion couplings of butane-1,4-diyl and pentane-1,5-diyl. The results were (1) the electronic couplings calculated from the two perturbative methods were in reasonable agreement with those from a non-perturbative method (one-half value of the energy difference between the ground and first excited states), (2) the main tunneling pathways consisted of a small number of lower-order super-exchange pathways where bonding, anti-bonding, or extra-valence-shell orbitals were used once or twice, and (3) the interference among a huge number of higher-order super-exchange pathways significantly contributed to the overall electronic coupling, whereas each of them contributed only fractionally. Our method can adequately take into account both effects of non-dynamical electron correlation and orbital relaxation. Comparing with the analyses based on the Koopmans' theorem (ignoring both effects) and the ORMAS-CIs from frozen localized reference orbitals (ignoring the effect of orbital relaxation), we discuss these effects.

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“…The precise relevance of permutation-based similarity-aided level crossing [22,36] behind higher-q(v) values seems to be another interesting subproblem in stopping theory. The Bethe limit, especially for metals with their dense electron gas, is not a simple cumulative sum of isolated atomic contributions [37].…”

Section: Discussionmentioning

confidence: 99%

Two-channel approach to the average retarding force of metals for slow singly ionized projectiles

Nágy

Aldazabal

2020

Phys. Rev. A

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Based on the fundamental momentum-transfer theorem [B. A. Lippmann, Phys. Rev. Lett. 15, 11 (1965)], a contribution to the retarding force of metallic systems for slow intruders is derived. This contribution is associated with sudden charge-changing cycles during the path of projectiles. The sum of this and the well-known conventional contributions, both expressed in terms of scattering phase shifts, is used to discuss experimental data obtained for different targets. It is found that our two-channel modeling, with two nonlinear channels, improves the agreement between data and theory and thus, as predictive modeling, can contribute to the desired convergence between experimental and theoretical attempts at the retarding force.

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Basis set limitations on the ab initio calculation of stopping cross-sections via generalized oscillator strengths

Cited by 7 publications

References 22 publications

Ghost transmission: How large basis sets can make electron transport calculations worse

Ghost transmission: How large basis sets can make electron transport calculations worse

Pathway analysis of super-exchange electronic couplings in electron transfer reactions using a multi-configuration self-consistent field method

Two-channel approach to the average retarding force of metals for slow singly ionized projectiles

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