Infrared radiation, and

In order to achieve a reasonable signal strength from the nonlinear response of approximately one atomic monolayer at an interface, a laser source with high peak power is generally required. Conuuon sources include Q-switched ( 10 ns pulsewidth) and mode-locked ( 100 ps) Nd YAG lasers, and mode-locked ( 10 fs-1 ps) Ti sapphire lasers. Broadly tunable sources have traditionally been based on dye lasers. More recently, optical parametric oscillator/amplifier (OPO/OPA) systems are coming into widespread use for tunable sources of both visible and infrared radiation. 

The focus of this chapter is photon spectroscopy, using ultraviolet, visible, and infrared radiation. Because these techniques use a common set of optical devices for dispersing and focusing the radiation, they often are identified as optical spectroscopies. For convenience we will usually use the simpler term spectroscopy in place of photon spectroscopy or optical spectroscopy however, it should be understood that we are considering only a limited part of a much broader area of analytical methods. Before we examine specific spectroscopic methods, however, we first review the properties of electromagnetic radiation. 

Optical Properties. Teflon FEP fluorocarbon film transmits more ultraviolet, visible light, and infrared radiation than ordinary window glass. The refractive index of FEP film is 1.341—1.347 (74). 

Additions to the PLM include monochromatic filters or a monochromator to obtain dispersion data (eg, the variation in refractive index with wavelength). By the middle of the twentieth century, ultraviolet and infrared radiation were used to increase the identification parameters. In 1995 the FTIR microscope gives a view of the sample and an infrared absorption pattern on selected 100-p.m areas (about 2—5-ng samples) (37). 

Radiation from the sun includes significant ultraviolet and infrared radiation in addition to visible radiation. Contributions of each type to the radiation that reaches Earth s surface are reduced significantly... 

Tan, M., Chua, K.J., Mujumdar, A.S., and Chou, S.K. 2001. Effect of osmotic pre-treatment and infrared radiation on drying rate and color changes during drying of potato and pineapple. Dry. Technol. 19, 2193-2207. 

This photograph shows a simple spectrophotometer, which measures the amount of visible light that is ahsorhed hy a coloured solution. More sophisticated devices can measure the absorption of ultraviolet and infrared radiation. 

Absorption, emission, and Infrared radiation Transmitted infrared radiation... 

Cold and soft radio, microwave and infrared radiation. Telescopes sensitive to the gentle radiation of the infrared unveil some of the more tender scenes in space, such as cloud formation and the birth of stars. They... 

Ascard, J. 1998. Comparison of flaming and infrared radiation techniques for thermal weed control. Weed Research 38 69-76. 

The selective absorption of ultraviolet, visible and infrared radiation by molecules is explained in a descriptive manner that stresses how the noncontinuous energy requirements of chemical substances can only be satisfied by photons that have energy values equivalent to that of the differences in energy levels of the molecule in question. The meaning and quantitative significance of Beer s Law is briefly discussed. The components of a simple spectrophotometer are illustrated, accompanied by a demonstration of the operation of a spectrophotometer in the laboratory. Actual applications of the techniques of spectrophotometry are described during the presentation of relevent topics, for example, in drug identification. 

The frequencies at the red and infrared radiations inside the etalon Fabry-Perot cavity are determined by the resonant condition /10/... 

T class rating of an Y-luminaire with an incandescent lamp is determined by the power rating of the lamp and the part of radiation which escapes from the luminaire, mainly visible light and infrared radiation. A blue glass cuts down the radiation in the visible part and raises the temperature profile. The original T class rating may be passed... 

The population of the molecular energy levels in interstellar space is determined by microwave and infrared radiation and by collisions with various collision partners (including dust grains) having kinetic temperatures between 5 °K and < 100 °K. 

The electromagnetic spectrum including visible and infrared radiation is discussed in Chapter 12. 

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