The theory of molecular two-photon spectroscopy in the gas phase

Metz, F.; Howard, Willis E.; Wunsch, L.; Neusser, H. J.; Schlag, E. W.

doi:10.1098/rspa.1978.0174

Cited by 66 publications

(5 citation statements)

References 12 publications

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“…This gives a more intuitive picture of the symmetries involved in the excitation process. It may be noted that the isotropic cross section obtained by averaging over an isotropic ensemble of non-rotating molecules corresponds also to the one obtained for rotating molecules, if in the latter case the rotational structure of the transitions is not experimentally resolved, as was shown by Metz et al (1978).…”

Section: The Multiphoton Ionization Cross Section Of a Diatomic Moleculementioning

confidence: 77%

Photoluminescence and X-Ray Photoelectron Study of AlGaAs/GaAs Near-Surface Quantum Wells Passivated by a Novel Interface Control Technique

Kodama¹,

Hashizume²,

Hasegawa³

1995

Jpn. J. Appl. Phys.

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Generalized cross sections for two-, three-, and four-photon ionization of H 2 by linearly polarized laser light have been calculated. Three different situations are considered: the laser polarization being parallel or perpendicular to the internuclear axis and the case of an isotropical distribution of H 2 molecules. The main features of the spectra are discussed. In order to assess the reliability of the results, two completely different ab initio methods have been developed and used for the parallel orientation; good agreement is found between them. The impact of the present results on the question of alignment of molecules in laser fields is discussed.

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Section: The Multiphoton Ionization Cross Section Of a Diatomic Moleculementioning

confidence: 77%

Photoluminescence and X-Ray Photoelectron Study of AlGaAs/GaAs Near-Surface Quantum Wells Passivated by a Novel Interface Control Technique

Kodama¹,

Hashizume²,

Hasegawa³

1995

Jpn. J. Appl. Phys.

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“…Thus, the temporal evolution of χ (3) is computed as the interferogram of damped harmonic oscillations, at the Raman frequencies ω (v i ,Ji)→(v f ,J f ) and with damping coefficients Γ (v i ,Ji)→(v f ,J f ) dominated by the collisional rotational energy transfer (RET) at atmospheric pressure, 65 -weighted by the semi-classical transition probabilities. 66 Thus, Eq. ( 4) introduces in the time-domain CRS model the spectroscopic properties of the Raman-active species, which in turn depend on the chemical structure of the molecule considered.…”

Section: Time-domain Crs Modelmentioning

confidence: 99%

The ro-vibrational ν2 mode spectrum of methane investigated by ultrabroadband coherent Raman spectroscopy

Mazza

Thornquist

Castellanos

et al. 2023

The Journal of Chemical Physics

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We present the first experimental application of coherent Raman spectroscopy (CRS) on the ro-vibrational ν2 mode spectrum of methane (CH4). Ultrabroadband femtosecond/picosecond (fs/ps) CRS is performed in the molecular fingerprint region from 1100 to 2000 cm−1, employing fs laser-induced filamentation as the supercontinuum generation mechanism to provide the ultrabroadband excitation pulses. We introduce a time-domain model of the CH4 ν2 CRS spectrum, including all five ro-vibrational branches allowed by the selection rules Δv = 1, Δ J = 0, ±1, ±2; the model includes collisional linewidths, computed according to a modified exponential gap scaling law and validated experimentally. The use of ultrabroadband CRS for in situ monitoring of the CH4 chemistry is demonstrated in a laboratory CH4/air diffusion flame: CRS measurements in the fingerprint region, performed across the laminar flame front, allow the simultaneous detection of molecular oxygen (O2), carbon dioxide (CO2), and molecular hydrogen (H2), along with CH4. Fundamental physicochemical processes, such as H2 production via CH4 pyrolysis, are observed through the Raman spectra of these chemical species. In addition, we demonstrate ro-vibrational CH4 v2 CRS thermometry, and we validate it against CO2 CRS measurements. The present technique offers an interesting diagnostics approach to in situ measurement of CH4-rich environments, e.g., in plasma reactors for CH4 pyrolysis and H2 production.

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“…A strong band is located at an excess energy of 1565 cm −1 . It is useful to discuss the polarization behavior in terms of the theory of gas phase two-photon transitions in polyatomic molecules [24,25]. In Ref.…”

Section: Two-photon-excitation Spectrummentioning

confidence: 99%

Two-Photon Spectroscopy of Jet-Cooled Benzonitrile: New Results for a Charge Transfer Molecule

Clara¹,

Siglow²,

Neusser³

2001

Zeitschrift Für Physikalische Chemie

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We compare the first jet-cooled two-photon fluorescence excitation spectrum of benzonitrile with its one-photon spectrum measured by resonance-enhanced multi-photon ionization (REMPI). Both spectra include the pure electronic transition and one vibrationally induced transition. The inducing mode is the ν 31 in the one-photon spectrum and the ν 27 in the two-photon spectrum. This is similar to benzene, where the corresponding vibration ν 6 induces a transition in the one-photon and the corresponding vibration ν 14 induces a transition in the two-photon spectrum. The one-photon spectrum shows no vibronic bands above 2160 cm −1 . This is ascribed to small Franck-Condon factors for the second progression members of totally symmetric vibrations. The two-photon fluorescence excitation spectrum has a cut off at the higher excess energy of 3000 cm −1 pointing to a nonradiative relaxation channel similar to benzene. No indication for a charge transfer process in the first electronic state of benzonitrile was found up to an excess energy of 3000 cm −1 .

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The theory of molecular two-photon spectroscopy in the gas phase

Cited by 66 publications

References 12 publications

Photoluminescence and X-Ray Photoelectron Study of AlGaAs/GaAs Near-Surface Quantum Wells Passivated by a Novel Interface Control Technique

Photoluminescence and X-Ray Photoelectron Study of AlGaAs/GaAs Near-Surface Quantum Wells Passivated by a Novel Interface Control Technique

The ro-vibrational ν2 mode spectrum of methane investigated by ultrabroadband coherent Raman spectroscopy

Two-Photon Spectroscopy of Jet-Cooled Benzonitrile: New Results for a Charge Transfer Molecule

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