Continuum states of the hydrogen molecule with the R‐Matrix method

Tennyson, Jonathan; Noble, C. J.; Burke, P G

doi:10.1002/qua.560290502

Cited by 50 publications

(25 citation statements)

References 17 publications

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“…3. Fixed-nuclei (equilibrium) and vibrationally averaged effective dipole asymmetry parameter β 2 for one-photon ionization of H 2 compared with experiments of Marr et al [47], Southworth et al [48], Parr et al [49], and Zimmermann et al [50] and an earlier stationary R-matrix calculation by Tennyson et al [51] with a different molecular model. et al [44].…”

Section: B Two-photon Ionizationmentioning

confidence: 91%

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Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

et al. 2020

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The ab initio R-matrix with time method has recently been extended to allow simulation of fully nonperturbative multielectron processes in molecules driven by ultrashort arbitrarily polarized strong laser fields. Here we demonstrate the accuracy and capabilities of the current implementation of the method for two targets: We study single-photon and multiphoton ionization of H 2 and one-photon and strong-field ionization of H 2 O and compare the results to available experimental and theoretical data as well as our own time-independent R-matrix calculations. We obtain a highly accurate description of total and state-to-state single-photon ionization of H 2 O and, using a simplified coupled-channel model, we show that state coupling is essential to obtain qualitatively correct results and that its importance as a function of laser intensity changes. We find that electron correlation plays a more important role at low intensities (up to approximately 50 TW/cm 2).

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Section: B Two-photon Ionizationmentioning

confidence: 91%

“…In Fig. 2 the RMT cross sections shown were obtained for very long pulses (greater than 100 cycles); for the ATZ basis set we tested the use of Marr et al [47] Southworth et al [48] Tennyson et al [51] Parr et al [49] Zimmermann et al [50] FIG. 3.…”

Section: B Two-photon Ionizationmentioning

confidence: 99%

Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

et al. 2020

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“…The factor cos(kr) could have been replaced by sin(kr)/kr: using the identity and an OHGF as d sin(kr) cos(kr) = r (3) y",~~"(r) lim d "e ' cos(kr) . R-os" a~' az" (2) It should be noted that instead of HGF's we could many formulas that will be derived in the following section hold also for sin(kr)/kr with only minor changes.…”

Section: Oscillating Hermite Gaussian Functionsmentioning

confidence: 99%

“…Several techniques originally proposed for describing scattering processes in molecules have been successfully extended to the calculation of photoionization cross sections (e.g. , the linear algebraic method [1], the iterative Schwinger method [2], and the R-matrix method [3]). In such techniques basis sets for the bound orbitals and numerical representations of the continuum orbitals are used.…”

Section: Introductionmentioning

confidence: 99%

Alternative basis functions forL2calculations on the molecular continuum. I. The basic prototype integrals

Fortunelli¹,

Carravetta²

1992

Phys. Rev. A

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Alternative square-integrable (L ) basis functions, the oscillating Hermite Gaussian functions (OHGF's), are proposed for describing the continuum orbitals in L calculations on molecules. Each function is the product of a Hermite Gaussian function {HGF), which gives the proper dumping and angular factor, and a radial trigonometric function, cos(kr ), which describes the oscillating asymptotic behavior of a continuum orbital. Analytic expressions for the oneand two-electron integrals involving stype OHGF's and many-center s-type HGF's are derived and their numerical implementation is discussed in detail. The present proposal of adopting a mixed basis set of OHGF's and many-center HGF's for the L description of bound and continuum molecular states is compared with the other types of basis functions currently employed. With respect to these, it requires a greater computational effort in the integral evaluation, but it also allows an accurate description of the electronic continuum in general polyatomic systems. PACS number{s): 31.1S.+q, 02.60.+ y

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“…In the time‐independent approach, various techniques have been proposed for treating the boundary conditions of the Schrödinger equation. In the complex Kohn method, the continuum wave function is calculated by a mixture of many

L^{2}

basis functions and a small number of non‐

L^{2}

basis functions that satisfy the exact boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

Calculation of photoionization differential cross sections using complex Gauss‐type orbitals

Matsuzaki

Yabushita

2017

J Comput Chem

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Accurate theoretical calculation of photoelectron angular distributions for general molecules is becoming an important tool to image various chemical reactions in real time. We show in this article that not only photoionization total cross sections but also photoelectron angular distributions can be accurately calculated using complex Gauss-type orbital (cGTO) basis functions. Our method can be easily combined with existing quantum chemistry techniques including electron correlation effects, and applied to various molecules. The so-called two-potential formula is applied to represent the transition dipole moment from an initial bound state to a final continuum state in the molecular coordinate frame. The two required continuum functions, the zeroth-order final continuum state and the first-order wave function induced by the photon field, have been variationally obtained using the complex basis function method with a mixture of appropriate cGTOs and conventional real Gauss-type orbitals (GTOs) to represent the continuum orbitals as well as the remaining bound orbitals. The complex orbital exponents of the cGTOs are optimized by fitting to the outgoing Coulomb functions. The efficiency of the current method is demonstrated through the calculations of the asymmetry parameters and molecular-frame photoelectron angular distributions of H2+ and H2 . In the calculations of H2 , the static exchange and random phase approximations are employed, and the dependence of the results on the basis functions is discussed. © 2017 Wiley Periodicals, Inc.

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Continuum states of the hydrogen molecule with the R‐Matrix method

Cited by 50 publications

References 17 publications

Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

Alternative basis functions forL2calculations on the molecular continuum. I. The basic prototype integrals

Calculation of photoionization differential cross sections using complex Gauss‐type orbitals

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