R-Matrix Theory of Atomic, Molecular and Optical Processes

Burke, P G; Noble, C. J.; Burke, V.M.

doi:10.1016/s1049-250x(06)54005-4

Cited by 111 publications

(154 citation statements)

References 232 publications

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“…The General Relativistic Atomic Structure Package (grasp) (Dyall et al 1989;Grant 2007) formulates and diagonalises a Dirac-Coulomb Hamiltonian (Grant 2007) to produce the relativistic orbitals for input to the Dirac Atomic R-matrix Code (darc) (Chang 1975;Norrington & Grant 1981;Grant 2007;Burke 2011) to obtain the photoionization (PI) cross sections. These darc codes are currently running efficiently on a variety of world-wide parallel High Performance Computer (hpc) architectures (Ballance 2016;McLaughlin et al , 2016McLaughlin et al , 2017.…”

Section: Photoionization Calculationsmentioning

confidence: 99%

Single photoionization of the Zn ii ion in the photon energy range 17.5–90.0 eV: experiment and theory

Hinojosa

Davis

Covington

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Measurements of the single photoionization cross section of Cu-like Zn + ions are reported in the energy (wavelength) range 17.5 eV (709Å) to 90 eV (138Å). The measurements on this trans-Fe element were performed at the Advanced Light Source synchrotron radiation facility in Berkeley, California at a photon energy resolution of 17 meV using the photon-ion merged-beams end-station. Below 30 eV the spectrum is dominated by excitation autoionizing resonance states. The experimental results are compared with large-scale photoionization cross-section calculations performed using a Dirac Coulomb R-matrix approximation. Comparison are made with previous experimental studies, resonance states are identified and contributions from metastable states of Zn + determined.

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Section: Photoionization Calculationsmentioning

confidence: 99%

Single photoionization of the Zn ii ion in the photon energy range 17.5–90.0 eV: experiment and theory

Hinojosa

Davis

Covington

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…(8), α n 1 l 1 n 2 l 2 ,k , are the normalised 5 eigenvectors obtained when the real symmetric matrix,…”

Section: Hamiltonian Matrix Elements Within a Subregionmentioning

confidence: 99%

2DRMP: A suite of two-dimensional R-matrix propagation codes

Scott¹,

Scott²,

Burke³

et al. 2009

Computer Physics Communications

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“…Notice that, in order to perform the integral over R in equation (1), this wave function must be obtained at different values of R. Several accurate methods have been successfully developed to evaluate ψ 0+ αlαǫα (r, R). Among them, it is worth mentioning (i) the discretized close-coupling (DCC) method [12,[17][18][19] and the convergent close-coupling (CCC) method [20][21][22], in which the electronic wave function is written as a combination of products of target and scattering electronic wave functions with the appropriate boundary conditions, (ii) the exterior complex scaling (ECS) method [23][24][25], in which the electronic coordinates are scaled in the complex plane beyond a certain (usually large) distance r 0 thus ensuring the correct asymptotic behavior for r i < r 0 , and (iii) the Rmatrix method (and its many extensions, see, e.g., [26][27][28] and references therein), in which the problem is first solved within a sphere of finite size and then the asymptotic behavior is switched on later from outside the sphere. In principle, all these methods can be implemented by using different basis sets and/or grid methods.…”

Section: Summary Of Existing Theoriesmentioning

confidence: 99%

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

Martín¹

2007

J. Phys.: Conf. Ser.

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Abstract. An overview of recent theoretical progress to accurately describe non dissociative and dissociative ionization of molecules exposed to synchrotron radiation and ultrashort uv/xuv laser pulses is presented. The success of recent theoretical approaches rely on their ability to account for both the electronic and nuclear degrees of freedom. This is essential to describe the delicate interplay between the electronic motion and the molecule's vibration, especially in those cases where ionization occurs in a time scale comparable to that of the vibrational motion. Some of the most successful applications and the new physics that has emerged by comparing with recent kinematically complete experiments on H2 and D2 will be discussed. IntroductionMolecular ionization is one of the most elementary processes that occurs in the upper atmosphere [1] and in interstellar molecular clouds [2]. Since in molecules the absorbed energy is shared between electronic and nuclear degrees of freedom, the remaining molecular ion can be left in an excited vibrational or dissociative state. This is at variance with atomic ionization where the energy is entirely absorbed by the electrons. In early pictures of molecular ionization, the nuclear motion was either ignored or described in terms of the Franck-Condon (FC) approximation, in which electronic processes occurring at the equilibrium position of the nuclei are weighted by the squared overlap between the initial and final vibrational states. With the advent of kinematically complete experiments [3,4], in which the momenta of all charged particles is determined, new phenomena with an intrinsic molecular origin have been discovered (see, e.g., [5][6][7][8][9][10][11]). Also the above pictures have been revealed to be incomplete. In this manuscript, the important role of nuclear dynamics in molecular ionization produced by synchrotron radiation and ultrashort pulses will be demonstrated by means of recent ab initio theoretical calculations that account for all electronic and vibrational degrees of freedom.In particular, recent results for electron angular distributions from fixed-in-space molecules will be analyzed and compared with kinematically complete photoionization experiments using synchrotron radiation. These include double and single photoionization of H 2 (D 2 ). The range of excess photon energies considered goes from a few to several hundreds of eV. Also, multiphoton ionization of molecules by vuv ultrashort pulses will be discussed. In particular, the new physics that can be expected by varying pulse duration and intensity will be analyzed.

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R-Matrix Theory of Atomic, Molecular and Optical Processes

Cited by 111 publications

References 232 publications

Single photoionization of the Zn ii ion in the photon energy range 17.5–90.0 eV: experiment and theory

Single photoionization of the Zn ii ion in the photon energy range 17.5–90.0 eV: experiment and theory

2DRMP: A suite of two-dimensional R-matrix propagation codes

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

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