Influence of large permanent dipoles on molecular orbital tomography

et al. 2017

Phys. Rev. A

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We show that the processes of π-π * transitions imprint themselves on the high-harmonic spectra when conjugated molecules interact with intense femtosecond laser pulses. It is found that a noninteger order peak appears in the harmonic spectrum with the photon energy equaling the excitation energy of the π-π * excitation. Further studies prove that this radiation is caused by the π-π * transition. The transition signals are prominent and can be easily measured as the corresponding radiation intensities are comparable to those of integer order harmonics. Our results pave the way for the study of excited-state electron-ion dynamics using high-harmonic spectroscopy. In comparison to the traditional absorption spectroscopy method relying on the synchrotron radiation source, the present approach is easily accessible for the use of a tabletop laser-based source. Furthermore, our study also provides a potential tool to probe the π-π * transition processes in femtosecond resolution.

Section: Introductionmentioning

confidence: 99%

Probing the π−π* transitions in conjugated compounds with an infrared femtosecond laser

Liu

et al. 2017

Phys. Rev. A

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“…In the past two decades, HHG has been intensively investigated for its potential applications in experimentally generating a coherent attosecond pulse [1,2] in the extreme ultraviolet (XUV) and soft x-ray regions [3]. The availability of isolated attosecond pulses has successfully opened new research areas for probing ultrafast processes of physics, chemistry and biology with unprecedented temporal and spatial resolutions [4][5][6][7][8][9][10][11]. For example, it has been shown that an attosecond XUV pulse can be used to study inner-shell electron dynamics in atoms and molecules [12,13].…”

Section: Introductionmentioning

confidence: 99%

Near-circularly polarized single attosecond pulse generation from nitrogen molecules in spatially inhomogeneous laser fields

Zhang

Yang

J. Phys. B: At. Mol. Opt. Phys.

et al. 2015

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The generation of an attosecond pulse in nitrogen molecules using spatially inhomogeneous laser fields is investigated by numerically solving the time-dependent Schrödinger equation. It is found that an isolated attosecond pulse with elliptical polarization can be generated using linearly polarized laser fields. By changing polarization direction with respect to the molecular axis, the ellipticity of the attosecond pulse can be easily controlled. At some specific angles, the intensities of the two mutually vertical harmonic components, parallel and perpendicular to the driving laser polarization direction, are comparable. Additionally, the relative phase between the two components is about π/2. As a result, it supports the generation of the isolated near-circularly polarized attosecond pulse with a duration of 155 as.

“…These results are due to the symmetry property of the orbitals and the feature of the inverse Fourier transform in the limited k-space. Besides the above discussed orbitals with symmetry or antisymmetry, the orbital can also be nonsymmetrically distributed, the reconstruction of which was discussed in [18].…”

mentioning

confidence: 99%

“…Besides the above discussed orbitals with symmetry or antisymmetry, the orbital can also be nonsymmetrically distributed, the reconstruction of which was discussed in [18].…”

mentioning

confidence: 99%

Tomographic reconstruction of molecular orbitals with twofold mirror antisymmetry: Overcoming the nodal plane problem

Qin

et al. 2013

Phys. Rev. A

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We propose a new method to overcome the nodal plane problem for the tomographic reconstruction of molecular orbitals with twofold mirror antisymmetry in the length form based on high-order harmonic generation. It is shown that, by carrying out the reconstruction procedure in the rotating laboratory frame using the component of the dipole moment parallel to the electron recollision direction, the nodal plane problem is avoided and the target orbital is successfully reconstructed. Moreover, it is found that, the proposed method can completely avoid the additional artificial lobes found in the results from the traditional method in the velocity form and therefore provides a more reliable reproduction of the target orbital.