Highly excited states of <i>gerade</i> symmetry in molecular nitrogen

Lange, A. de; Lang, Ruediger; Zande, W. van der; Ubachs, Wim

doi:10.1063/1.1468220

Cited by 9 publications

(9 citation statements)

References 47 publications

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“…The exact NIR-induced coupling mechanism that allows for the observation of the quantum beating in the b 0 valence state cannot be determined from the experimental observations alone. In the energy range accessible by the NIR pulse, dark states of both Rydberg and valence character have been found [38]. Of particular interest is an avoided crossing between the a 00 1 R g + Rydberg and 1 R g + (II) valence state, confirmed experimentally by considerable energetic perturbations of the observed vibrational levels of these two states [39,40].…”

Section: Discussionmentioning

confidence: 85%

Attosecond transient absorption spectroscopy of molecular nitrogen: Vibrational coherences in the b′ 1Σ+u state

Warrick

Bækhøj

Cao

et al. 2017

Chemical Physics Letters

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Nuclear and electronic dynamics in a wavepacket comprising bound Rydberg and valence electronic states of nitrogen from 12 to 15 eV are investigated using attosecond transient absorption. Vibrational quantum beats with a fundamental period of 50 femtoseconds persist for a picosecond in the b 0 1 R + u valence state. Multi-state calculations show that these coherences result primarily from near infraredinduced coupling between the inner and outer regions of the b 0 1 R + u state potential and the dark a 00 1 R + g state. The excellent spectral and temporal resolution of this technique allows measurement of the anharmonicity of the b 0 1 R + u potential directly from the observed quantum beats.

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Section: Discussionmentioning

confidence: 85%

Attosecond transient absorption spectroscopy of molecular nitrogen: Vibrational coherences in the b′ 1Σ+u state

Warrick

Bækhøj

Cao

et al. 2017

Chemical Physics Letters

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“…The number and shape of the accessible dark states determine the magnitude of the transition dipoles that couple the bright states and will affect the strengths of the absorption oscillations through the population-transfer amplitude terms, | A n 1 ( t – τ)|, in eq . Four dark Rydberg states have been identified in the 14 eV region built on the A and X ion state cores that are good candidates to mediate the two-photon coupling pathway . The two experimentally observed dark states with valence state character in nitrogen are located too low in energy to be the intermediate state for these transitions. − …”

Section: Discussionmentioning

confidence: 99%

“…Four dark Rydberg states have been identified in the 14 eV region built on the A and X ion state cores that are good candidates to mediate the two-photon coupling pathway. 57 The two experimentally observed dark states with valence state character in nitrogen are located too low in energy to be the intermediate state for these transitions. 57−59 In Figure 5, Fourier spectra are presented showing the relevant energy ranges giving rise to the observed subcycle dynamics.…”

Section: Discussionmentioning

confidence: 99%

Probing the Dynamics of Rydberg and Valence States of Molecular Nitrogen with Attosecond Transient Absorption Spectroscopy

et al. 2016

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An attosecond pulse is used to create a wavepacket in molecular nitrogen composed of multiple bound and autoionizing electronic states of Rydberg and valence character between 12 and 16.7 eV. A time-delayed, few-femtosecond, near-infrared (NIR) laser pulse is used to couple individual states in the wavepacket to multiple neighboring states, resulting in time-dependent modification of the absorption spectrum and revealing both individual quantum beats of the wavepacket and the energy shifts of the excited states in the presence of the strong NIR field. The broad bandwidth of the attosecond pulse and high energy resolution of the extreme ultraviolet spectrometer allow the simultaneous observation of time-dependent dynamics for many individual vibrational levels in each electronic state. Quantum beating with periods from 1.3 to 12 fs and transient line shape changes are observed among vibrational levels of a progression of electronically autoionizing Rydberg states leading to the excited A (2)Πu N2(+) ion core. Vibrational levels in the valence b (1)Πu state exhibit 50 fs oscillation periods, revealing superpositions between individual vibrational levels within this state. Comparisons are made to previous studies of electronic wavepackets in atoms that highlight similarities to atomic behavior yet illustrate unique contributions of the diatomic molecular structure to the wavepacket, including the influence of different electronic potentials and vibrational-level-specific electronic dynamics.

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“…24 Higher energy Rydberg character dark states have also been identified using multiphoton excitation at energies above 14 eV. 27,28 These include the k 4dπg state 27 and the d3 3d g state, 29,30 which are Rydberg states built on the X N2 + ion core.…”

Section: Overview Of Nitrogen Electronic State Spectroscopymentioning

confidence: 99%

Multiple pulse coherent dynamics and wave packet control of the N₂a′′¹Σ+g dark state by attosecond four-wave mixing

et al. 2018

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Nonlinear multidimensional spectroscopy is ubiquitous in the optical and radio frequency regions as a powerful tool to access structure and dynamics. The extension of this technique into the extreme ultraviolet (XUV) region with attosecond pulses holds promise for probing electronic dynamics and correlations with unprecedented time and spatial resolution. In this work, we use noncollinear four-wave mixing of a weak XUV attosecond pulse train (11-17 eV) and few-femtosecond NIR pulses (800 nm) to spectroscopically and dynamically probe the dipole-forbidden double-well potential of the a'' 1∑+g electronic state of nitrogen. The results demonstrate optical coupling of the inner and outer limits of the initial XUV-prepared vibrational wave packet in the valence character b' 1∑+u state to the inner and outer wells, respectively, of the a'' 1∑+g double well state by 800 nm light. Two four-wave mixing schemes with different pulse timing sequences and noncollinear beam geometries are used (one NIR pulse collinear and one NIR pulse noncollinear versus both NIR pulses noncollinear to the XUV beam) to measure the a'' dark state energetic structure and to control the dynamical preparation and motion of a dark state wave packet by selective population of either the inner Rydberg or outer valence-character potential well. Experimental measurements of the a'' 1∑+g outer well vibrational spacing and anharmonicity closely match the values theoretically predicted for this previously unobserved state.

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Highly excited states of gerade symmetry in molecular nitrogen

Cited by 9 publications

References 47 publications

Attosecond transient absorption spectroscopy of molecular nitrogen: Vibrational coherences in the b′ 1Σ+u state

Attosecond transient absorption spectroscopy of molecular nitrogen: Vibrational coherences in the b′ 1Σ+u state

Probing the Dynamics of Rydberg and Valence States of Molecular Nitrogen with Attosecond Transient Absorption Spectroscopy

Multiple pulse coherent dynamics and wave packet control of the N₂a′′¹Σ+g dark state by attosecond four-wave mixing

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Highly excited states of gerade symmetry in molecular nitrogen

Cited by 9 publications

References 47 publications

Attosecond transient absorption spectroscopy of molecular nitrogen: Vibrational coherences in the b′ 1Σ+u state

Attosecond transient absorption spectroscopy of molecular nitrogen: Vibrational coherences in the b′ 1Σ+u state

Probing the Dynamics of Rydberg and Valence States of Molecular Nitrogen with Attosecond Transient Absorption Spectroscopy

Multiple pulse coherent dynamics and wave packet control of the N2a′′1Σ+g dark state by attosecond four-wave mixing

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Multiple pulse coherent dynamics and wave packet control of the N₂a′′¹Σ+g dark state by attosecond four-wave mixing