Middle-Range Infrared Absorption

Middle-Range Infrared Absorption Correlation Charts.8-39... 

MIDDLE-RANGE INFRARED ABSORPTION CORRELATION CHARTS... 

The following charts provide characteristic middle-range infrared absorptions obtained from particular functional groups on molecules (Refs. 1 and 2). These include a general mid-range correlation chart, a chart for aromatic absorptions, and a chart for carbonyl moieties. Charts for near infrared absorptions and for inorganic moieties can be found in the cited references. 

MIDDLE-RANGE INFRARED ABSORPTION CORRELATION CHARTS Thomas J. Bruno and Paris D.N. Svoronos... 

Figure 2.2-2 The visible, near, middle and far infrared region of the spectrum drawn in a scale linear in wavenumbers. The infrared (IR) and far-infrared (FIR) spectrum is recorded by absorption of light from a continuous spectrum in the range of A = 2.5. .. 100 pm = i) = 4000. .. 100 cm and A = 100. .. 1000 pm = 100. .. 10 cm". Raman spectra can be excited by monochromatic radiation, emitted by different lasers in the visible (VIS) or near-infrared range (NIR). Molecules emit Raman lines with a frequency difference AF to that of the exciting frequency >o between 0 and -f 4000 or - 4000 cm. Usually only the Raman spectrum which is shifted to. smaller wavenumbers, the Stokes Raman spectrum, is recorded. Its range is indicated by bars for different exciting lines Ar" " laser at 488 and 515 nm, HeNe laser at 623 nm, GaAs laser at 780 nm, and Nd YAG laser at 1064 nm.

In all ranges of the infrared, the near, middle, and far infrared (NIR, MIR, and FIR) mainly the absorption of radiation by a sample is evaluated. Emission spectra are only rarely recorded, even though they are a powerful tool for solving problems which cannot be investigated by other methods investigations of remote samples (in astronomy and for environmental analysis), of reactions of substances on catalysts, and of layers on surfaces (Mink and Keresztury, 1988) (Sec. 3.3.1). Other techniques of investigating surface layers, e.g., ATR technique and ellipsometry in the infrared range, are described in Sec. 6.4. 

---