什麼是光譜學

一種分析技術，用於鑑別化學元素和化合物，測量物質在外部能源的激發下，吸收或發射電磁波譜（包括γ射線、X射線、紫外輻射、可見光、紅外輻射、微波以及無線電頻率的輻射）中特徵波長的輻射能量，從而闡明其原子和分子結構。所用的儀器是分光鏡（用於直接觀察）和攝譜儀（用於記錄光譜）。實驗包括一個光源、一塊用來形成光譜的棱鏡或光柵、用來觀察或記錄光譜細節的探測器（視覺的、光電的、測輻射的或者攝影的）、測量波長和強度的裝置以及對測得的量作出解釋以識別它的化學身分，或給出關於它的原子和分子結構的線索。19世紀中葉用光譜技術分析太陽光譜而發現了氦、銫和銣。專門的光譜技術有拉曼光譜（參閱Raman, Chandrasekhara Venkata）、核磁共振、原子核四極矩共振、動態反射光譜、微波和γ射線光譜，以及電子自旋共振。亦請參閱mass spectrometry、spectrophotometry。

spectroscopy

Branch of analysis devoted to identifying elements and compounds and elucidating atomic and molecular structure by measuring the radiant energy absorbed or emitted by a substance at characteristic wavelengths of the electromagnetic spectrum (including gamma ray, X ray, ultraviolet, visible light, infrared, microwave, and radio-frequency radiation) on excitation by an external energy source. The instruments used are spectroscopes (for direct visual observation) or spectrographs (for recording spectra). Experiments involve a light source, a prism or grating to form the spectrum, detectors (visual, photoelectric, radiometric, or photographic) for observing or recording its details, devices for measuring wavelengths and intensities, and interpretation of the measured quantities to identify chemicals identifications or give clues to the structure of atoms and molecules. Helium, cesium, and rubidium were discovered in the mid-19th century by spectroscopy of the sun's spectrum. Specialized techniques include Raman spectroscopy (see Chandrasekhara Venkata Raman), nuclear magnetic resonance (NMR), nuclear quadrupole resonance, dynamic reflectance spectroscopy, microwave and gamma ray spectroscopy, and electron spin resonance (ESR). See also mass spectrometry, spectrophotometry.