Strong non-adiabatic effects in C2D4+

Köppel, Horst; Cederbaum, Lorenz S.; Domcke, Wolfgang

doi:10.1016/0009-2614(84)87072-4

Cited by 209 publications

(435 citation statements)

References 16 publications

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“…Calculations of the vibronic level structure of HCO 2 and DCO 2 were made using the quasidiabatic Hamiltonian approach of Köppel, Domcke, and Cederbaum (KDC). 41 The parametrization of the Hamiltonian used in this work is, however, considerably more elaborate than in typical applications of the KDC method. While a full discussion of the theoretical approach taken in the HCO 2 and DCO 2 calculations will be deferred to a subsequent detailed theoretical paper, 42 it is appropriate to give an outline here.…”

Section: Sevi Spectra Of Hcomentioning

confidence: 99%

Vibronic Structure of the Formyloxyl Radical (HCO₂) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

et al. 2009

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We report high-resolution photoelectron spectra of HCO 2 -and DCO 2 -obtained with slow photoelectron velocity-map imaging. Well-resolved photodetachment transitions to the 2 A 1 and 2 B 2 states of the neutral radicals were observed. In addition, vibronic levels of the HCO 2 and DCO 2 radicals with up to 2000 cm -1 of internal energy were calculated using a quasidiabatic Hamiltonian approach and high-level ab initio calculations. Spectral simulations using the calculated levels were found to be in excellent agreement with the experimental spectra and used to assign many of its features. This study unambiguously determined that the 2 A 1 state is the ground state of both HCO 2 and DCO 2 , in contrast to earlier work that indicated the 2 B 2 state was the ground state for DCO 2 . For both isotopologs, the 2 B 2 state is a very low-lying excited state with term energies of T 0 ) 318 ( 8 cm -1 for HCO 2 and T 0 ) 87 ( 8 cm -1 for DCO 2 . The adiabatic electron affinities are determined to be EA(HCO 2 ) ) 3.4961 ( 0.0010 eV and EA(DCO 2 ) ) 3.5164 ( 0.0010 eV.

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Section: Sevi Spectra Of Hcomentioning

confidence: 99%

Vibronic Structure of the Formyloxyl Radical (HCO₂) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

et al. 2009

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“…However, it has been known for a long time that inclusion of the nuclear motion is extremely relevant to understand ionization spectra of polyatomic molecules even qualitatively. In particular, the presence of conical intersections is widespread and dominate the appearance of ionization spectra [105]. Thus accurate methods to compute the nuclear quantum dynamics in systems with up to 20-30 degrees of freedom have already been developed (see e.g.…”

Section: Discussionmentioning

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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“…The concept of diabatic states is useful in several fields, ranging from atom-atom collisions to molecular spectroscopy. [54][55][56] For two coupled electronic states, the matrix Hamiltonian describing the nuclear motion in the adiabatic representation can be written as [54][55][56] …”

Section: The Born-oppenheimer Approximationmentioning

confidence: 99%

“…In vibronic coupling theory, diabatic potentials are usually constructed by the fitting of the eigenvalues of a diabatic model Hamiltonian to adiabatic ab initio data. 56 …”

Section: The Born-oppenheimer Approximationmentioning

confidence: 99%

Jahn–Teller and spin–orbit coupling effects in transition-metal trifluorides

et al. 2011

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Strong non-adiabatic effects in C2D4+

Cited by 209 publications

References 16 publications

Vibronic Structure of the Formyloxyl Radical (HCO₂) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

Vibronic Structure of the Formyloxyl Radical (HCO₂) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

Jahn–Teller and spin–orbit coupling effects in transition-metal trifluorides

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Strong non-adiabatic effects in C2D4+

Cited by 209 publications

References 16 publications

Vibronic Structure of the Formyloxyl Radical (HCO2) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

Vibronic Structure of the Formyloxyl Radical (HCO2) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

Molecular ionization and dissociation using synchrotron radiation and ultrashort laser pulses

Jahn–Teller and spin–orbit coupling effects in transition-metal trifluorides

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Vibronic Structure of the Formyloxyl Radical (HCO₂) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations

Vibronic Structure of the Formyloxyl Radical (HCO₂) via Slow Photoelectron Velocity-Map Imaging Spectroscopy and Model Hamiltonian Calculations