SPECTROSCOPY

ContentsIntroductionHistoryTypesSpectrometer

INTRODUCTION

Spectroscopy is the study of the interaction between matter and electromagnetic radiationoriginated through the study of visible light dispersed according to its wavelength, by a prism

IntroductionSpectra Refers to:-the distribution of colors produced when white light is dispersed by a prism continuous change in wavelength from red, the longest wavelength, to violet, the shortest.  Spectroscopic data is represented byspectrum, a plot of the response of interest as a function of wavelength or frequency.

Conti…Spectroscopy Used in  Physical chemistry Analytical chemistry Research telescopes AstronomyRemote sensing

HistoryNewton's ConceptIn 1666–1672spectroscopy began with Isaac Newton's optics experimentsdescribe the rainbow of colors that combine to form white light and that are revealed when the white light is passed through a prism.

Joseph von Fraunhofer early 1800s made experimental advances with spectrometers that enabled spectroscopy to become a more precise and quantitative scientific technique.

TYPES OF SPECTROSCOPY

Conti…

Flame X-ray Atomic Emission Spectroscopy (AE) Atomic absorption spectroscopy (AA) Spark or arc (emission) spectroscopy

Conti… Visible/Ultraviolet (UV) Infrared (IR) and Near Infrared (NIR) Nuclear magnetic resonance

Atomic Emission Spectroscopy (AE)

uses atoms excited from the heat of a flame to emit light.

analysis can be done with a high resolution Polychromator to produce an emission intensity.

wavelength spectrum to detect multiple elements simultaneously.

Atomic absorption spectroscopy

A spectroanalytical procedure for the quantitative determination of chemical elements using the absorption of optical radiation (light) by free atoms in the gaseous state.

Mass Spectrometry

Is an analytical chemistry technique that helps identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions

19

Infrared Spectroscopy

Is the spectroscopy that deals with the infrared region of the electromagnetic spectrum that is light with a longer wavelength and lower frequency than visible light.

Spectrometer

A spectrometer is an apparatus to measure a spectrumIt shows intensity as a function of Wavelength Frequency Energy Momentum  Mass

Optical spectrometer Mass spectrometerTime-of-flight spectrometerMagnetic spectrometer

Optical Spectrometer

 show the intensity of light as a function of wavelength or of frequency

The deflection is produced either by refraction in a prism or by diffraction in a diffraction grating

Mass spectrometerA mass spectrometer is an analytical instrument that is used toidentify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratioabundance of gas-phase ions

Time-of-flight spectrometer

 determining the time of flight between two detectors

 if the velocity is known, masses can be determined