Definitions of introduction to spectroscopy

electromagnetic radiation Energy that is propagated through free space or material medium in the form of electromagnetic waves with a given frequencywavelength ( lambda) The spatial period of the wavefrequency ( nu)Number of waves pass a given space per unit of timeamplitudeHeight of the wavewave-particle dualityEnergy/photon has both wave-like and particle characteristics. Travels as a wave but also the energy is quantized, in the form of a photon.frequency x wavelength = speed of lightc= 2.998 x 10^8 m/sdiffraction when a wave encounters an obstacleinterference two or more waves can superimpose to form a resultant wave of greater or lower amplitude ( constructive or destructive waves)refraction Change in direction of a wave due to a change in transmission mediumdoppler effectchange in frequency of a wave for an observer moving relative to its sourcephotonquantum of lightenergy of the photon = Planck constant x frequencyPlanck constant = 6.626 x 10^-34 J/sSpectroscopyThe experimental observation of transitions of molecules between permitted energy levels as a result of absorption or emission of EM radiationAbsorptionMolecule is promoted to a higher energy level as a result of absorption of a photonEmission / fluorescenceMolecule relaxes to a lower-energy state and emits a photonspectraAmount of light absorbed per secondselection rulesTransitions only occur if they are allowed by selection rules. We distinguish gross and specific selection rules. Gross s. r. state a requirement for the atom/molecule to possess a particular propertySpecific selection rules state a restriction on the type of transition.