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Chapter 20: Q8P (page 525)

Deuterated triglycine sulfate (abbreviated DTGS) is a common ferroelectric infrared detector material. Explain how it works.

Short Answer

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Deuterated triglycine sulfate (DTGS) has a permanent electric polarization as a result of alignment of the molecules in the crystal. One part of the crystal is positively charged, while the opposite side is negative. The polarization is temperature dependent, so when the crystal absorbs infrared radiation, its temperature and polarization (voltage difference) change. The change in voltage is the detector pyroelectric signal.

Step by step solution

01

Step: 1 Definition of the deuterated triglycine sulfate (DTGS):

A deuterated triglycine sulfate (DTGS) mid-infrared spectrometer showing large and automatic signals of electrical polarization when the infrared beam incident affects its separation.

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Most popular questions from this chapter

Explain why the transmission spectrum is calculated from the quotient (sample transform) M(background transform) instead of the difference (sample transform) - (background transform).

Refer to the Fourier transform infrared spectrum in Figure 20-33.

(a) The interferogram was sampled at retardation intervals of1.2260×10-4cm. What is the theoretical wavenumber range (0 to ?) of the

spectrum?

(b) A total of 4 096 data points were collected from δ=-∆toδ=+∆. Compute the value of∆, the maximum retardation.

(c) Calculate the approximate resolution of the spectrum.

(d) The interferometer mirror velocity is given in the figure caption. How many microseconds elapse between each datum?

(e) How many seconds were required to record each interfero gram once?

(f) What kind of beam splitter is typically used for the region 400 to 4 000cm-1? Why is the region below 400cm-1not observed?

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Results of an electrochemical experiment are shown in the figure. In each case, a voltage is applied between two electrodes at timeand the absorbance of a solution decreases until the voltage is stepped back to its initial value at time. The upper traces show the average results for 100,300, and 1000 repetitions of the experiment. The measured signal-to-rms noise ratio in the upper trace is 60.0. Predict the signal-to-noise ratios expected for 300 cycles, 100 cycles, and 1 cycle and compare your answers with the observed values in the figure.
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