Dynamics in supercritical fluids studied using ultrafast pulse laser spectroscopy

Noritsugu Kometani, Yuji Hoshihara, Mark Maroncelli

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Solvation dynamics and rotational relaxation in supercritical fluids have been examined using the techniques of the subpicosecond laser spectroscopy. The fluorescence up-conversion technique has been employed to detect the fluorescence anisotropy decay of coumarin 153 in supercritical CO 2 (310 K) and CHF 3 (302, 310 K) over a wide density range. The rotational correlation times in supercritical CHF 3 exhibit the remarkable increase at 0.6 0.7 times ρ c, which implies that the local solvent density augmentation slows down the rotational dynamics in supercritical fluids. This conclusion is supported by computer simulations based on a 2-site model of fluoroform. The solvation dynamics of the probe 4-dimethylamino-4′-cyanostilbene have been measured in supercritical CHF 3 at 310 K using the optical Kerrgated emission technique, which appears to have captured most (∼90%) of the dynamics occurring over the accessible density range between 1.4-2.0ρ c. The measured spectral response exhibits a bimodal decay with ∼0.6 ps and ∼9 ps components and only a modest density dependence.

Original languageEnglish (US)
Pages (from-to)113-119
Number of pages7
JournalReview of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu
Volume16
Issue number2
DOIs
StatePublished - 2006

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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