TY - JOUR

T1 - Phase-sensitive detection in potential-modulated in situ absorption and probe beam deflection techniques

T2 - Theoretical considerations

AU - Stefan, I. C.

AU - Tolmachev, Y. V.

AU - Scherson, Daniel Alberto

PY - 2001/2/1

Y1 - 2001/2/1

N2 - A mathematical framework is presented for the quantitative analysis of in situ potential modulation spectroelectrochemical techniques based on phase-sensitive detection for the study of solution-phase redox systems under strict diffusion control. In the case of arrangements in which the probing beam is parallel to the electrode surface, the phase of the optical signal with respect to the applied potential, assuming negligible double-layer charging currents, was found to be proportional to y(ω/2D)1/2, where y is the distance normal to the electrode, ω is the frequency of the perturbating signal, and D is the diffusion coefficient of the species responsible for absorption or refraction. Good agreement was found between theoretical predictions and the few available experimental results for both absorption and probe beam deflection-type experiments. In particular, in the case of solutions containing the chromophore trianisylamine and nonabsorbing p-benzoquinone, the phase angle difference between absorption and diffraction calculated from theory and measured experimentally yielded a common value of ∼30°.

AB - A mathematical framework is presented for the quantitative analysis of in situ potential modulation spectroelectrochemical techniques based on phase-sensitive detection for the study of solution-phase redox systems under strict diffusion control. In the case of arrangements in which the probing beam is parallel to the electrode surface, the phase of the optical signal with respect to the applied potential, assuming negligible double-layer charging currents, was found to be proportional to y(ω/2D)1/2, where y is the distance normal to the electrode, ω is the frequency of the perturbating signal, and D is the diffusion coefficient of the species responsible for absorption or refraction. Good agreement was found between theoretical predictions and the few available experimental results for both absorption and probe beam deflection-type experiments. In particular, in the case of solutions containing the chromophore trianisylamine and nonabsorbing p-benzoquinone, the phase angle difference between absorption and diffraction calculated from theory and measured experimentally yielded a common value of ∼30°.

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U2 - 10.1021/ac000675k

DO - 10.1021/ac000675k

M3 - Article

C2 - 11217757

AN - SCOPUS:0035253705

SN - 0003-2700

VL - 73

SP - 527

EP - 532

JO - Analytical chemistry

JF - Analytical chemistry

IS - 3

ER -