An apparatus for quantitative high-harmonic generation spectroscopy in molecular vapours

McGrath, Felicity; Johnson, Allan S.; Austin, Dane R.; Hawkins, Peter G.; Wood, David; Miseikis, Lukas; Simpson, E. R.; Castillejo, Marta; Torres, Ricardo; Parker, Susan; Siegel, Thomas; Marangos, J. P.

doi:10.1063/1.4986037

Cited by 6 publications

(2 citation statements)

References 30 publications

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“…Great care was taken to ensure that spectral reshaping due to longitudinal phase mismatch or absorption was not present; these measures are further described in ref. 41 .…”

Section: Methodsmentioning

confidence: 99%

Extracting sub-cycle electronic and nuclear dynamics from high harmonic spectra

Austin

Johnson

McGrath

et al. 2021

Sci Rep

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We present a new methodology for measuring few-femtosecond electronic and nuclear dynamics in both atoms and polyatomic molecules using multidimensional high harmonic generation (HHG) spectroscopy measurements, in which the spectra are recorded as a function of the laser intensity to form a two-dimensional data set. The method is applied to xenon atoms and to benzene molecules, the latter exhibiting significant fast nuclear dynamics following ionization. We uncover the signature of the sub-cycle evolution of the returning electron flux in strong-field ionized xenon atoms, implicit in the strong field approximation but not previously observed directly. We furthermore extract the nuclear autocorrelation function in strong field ionized benzene cations, which is determined to have a decay of $$\tau _0 = 4 \pm 1$$ τ 0 = 4 ± 1 fs, in good agreement with the $$ \tau _0 = 3.5$$ τ 0 = 3.5 fs obtained from direct dynamics variational multi-configuration Gaussian calculations. Our method requires minimal assumptions about the system, and is applicable even to un-aligned polyatomic molecules.

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“…Great care was taken to ensure that spectral reshaping due to longitudinal phase mismatch or absorption was not present; these measures are further described in ref. 41 .…”

Section: Methodsmentioning

confidence: 99%

Extracting sub-cycle electronic and nuclear dynamics from high harmonic spectra

Austin

Johnson

McGrath

et al. 2021

Sci Rep

Self Cite

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“…7,11 Therefore, there is an effort to design the experimental setup in a way that reduces the sample consumption and minimizes contact with it. Experimental techniques that would benefit from such a reduction range from high order harmonics generation 8,12 over velocity map imaging, 13,14 hemispherical analyzers, 15 magnetic bottle spectrometers, 16,17 time-of-flight tubes, 18 and photon detection 19 to cold target recoil ion momentum spectroscopy (COLTRIMS)type reaction microscopes. 20 While only a small fraction of the sample is really "used," the major part has to be pumped out of the apparatus in order to maintain the high or ultrahigh vacuum.…”

Section: Introductionmentioning

confidence: 99%

Closed-loop recycling of rare liquid samples for gas-phase experiments

Fehre

Pitzer

Trinter

et al. 2021

Review of Scientific Instruments

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Many samples of current interest in molecular physics and physical chemistry exist in the liquid phase and are vaporized for use in gas cells, diffuse gas targets, or molecular gas jets. For some of these techniques, the large sample consumption is a limiting factor. When rare, expensive molecules such as custom-made chiral molecules or species with isotopic labels are used, wasting them in the exhaust line of the pumps is quite an expensive and inefficient approach. Therefore, we developed a closed-loop recycling system for molecules with vapor pressures below atmospheric pressure. Once filled, only a few valves have to be adjusted, and a cold trap must be moved after each phase of recycling. The recycling efficiency per turn exceeds 95%.

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