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Hamaguchi Lab.

Spectrophysical Chemistry bridges chemistry and biology


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Time-Resolved Infrared Spectroscopic System (short IR, mid IR) (10000-800cm-1)

Nanosecond Time-resolved Near-/mid-infrared Spectroscopic System

Fig. 1

Fig. 1. Setup

Fig. 2

Fig. 2. Apparatus

  • Scan limit: 10000cm-1
  • Sensitivity: ΔA < 10-6
  • Rep. rate: ∼ 1200Hz

Observation of Low-lying Excited-triplet States of Acetophenone (AP)

Solvent polarity and the photo-induced H abstraction rate of AP

Table 1. Rate
Solventkr [M-1s-1]

Inversion of the T1 and T2 state ordering of acetophenone accounts for this change in the reaction rate?

Fig. 3

Fig. 3.

Time-resolved near-/mid-infrared spectroscopy

Relative position of the T2 state can be determined by observing the transition between the T1 and T2 states.

Fig. 4

Fig. 4. Result

The infrared absorption band assignable to T2(π-π*)←T1(n-π*) electronic transition does not change aprreciably with solvent polarity!

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