Time- and angle-resolved photoemission spectroscopy with optimized high-harmonic pulses using frequency-doubled Ti:Sapphire lasersSteffen Eich
, Jurij Urbančič
, 2014, izvirni znanstveni članek
Opis: Time- and angle-resolved photoemission spectroscopy (trARPES) using femtosecond extreme ultraviolet high harmonics has recently emerged as a powerful tool for investigating ultrafast quasiparticle dynamics in correlated-electron materials. However, the full potential of this approach has not yet been achieved because, to date, high harmonics generated by 800 nm wavelength Ti:Sapphire lasers required a trade-off between photon flux, energy and time resolution. Photoemission spectroscopy requires a quasi-monochromatic output, but dispersive optical elements that select a single harmonic can significantly reduce the photon flux and time resolution. Here we show that 400 nm driven high harmonic extreme-ultraviolet trARPES is superior to using 800 nm laser drivers since it eliminates the need for any spectral selection, thereby increasing photon flux and energy resolution to <150 meV while preserving excellent time resolution of about 30 fs.
Najdeno v: ključnih besedah
Povzetek najdenega: ...emerged as a powerful tool for investigating ultrafast quasiparticle dynamics in correlated-electron materials. However, the...
Ključne besede: angle-resolved photoemission spectroscopy, ARPES, high harmonic generation, ultrafast surface science
Objavljeno: 20.04.2017; Ogledov: 2189; Prenosov: 0
Polno besedilo (1,80 MB)
Ultra-Fast-VUV Photoemission Study of UV Excited 2-NitrophenolPetra Rudolf
, Luca Poletto
, Fabio Frassetto
, Paolo Miotti
, Antti Kivimak̈i
, Monica de Simone
, Cesare Grazioli
, Barbara Ressel
, Giovanni De Ninno
, C. Spezzani
, Carlo Callegari
, Marcello Coreno
, A. Ciavardini
, Simona Fornarini
, Marco Pezzella
, Enrico Bodo
, Susanna Piccirillo
, 2019, izvirni znanstveni članek
Opis: The initial deactivation pathways of gaseous 2-nitrophenol excited at 268 nm were investigated by time-resolved photoelectron spectroscopy (TRPES) with femtosecond-VUV light, produced by a monochromatized high harmonic generation source. TRPES allowed us to obtain new, valuable experimental information about the ultrafast excited-state dynamics of 2-nitrophenol in the gas phase. In accord with recent ab initio on-the-fly nonadiabatic molecular dynamic simulations, our results validate the occurrence of an ultrafast intersystem crossing leading to an intermediate state that decays on a subpicosecond time scale with a branched mechanisms. Two decay pathways are experimentally observed. One probably involves proton transfer, leading to the most stable triplet aci-form of 2-nitrophenol; the second pathway may involve OH rotation. We propose that following intersystem crossing, an ultrafast fragmentation channel leading to OH or HONO loss could also be operative.
Najdeno v: ključnih besedah
Povzetek najdenega: ...obtain new, valuable experimental information about the ultrafast excited-state dynamics of 2-nitrophenol in the gas...
Ključne besede: Ultrafast photoemission, nitrophenol
Objavljeno: 12.02.2019; Ogledov: 906; Prenosov: 0
Polno besedilo (1,81 MB)