electromagnetic radiation

Energy that is propagated through free space or material medium in the form of electromagnetic waves with a given frequency

wavelength ( lambda)

The spatial period of the wave

frequency ( nu)

Number of waves pass a given space per unit of time

amplitude

Height of the wave

wave-particle duality

Energy/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 light
c= 2.998 x 10^8 m/s

diffraction

when a wave encounters an obstacle

interference

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 medium

doppler effect

change in frequency of a wave for an observer moving relative to its source

photon

quantum of light
energy of the photon = Planck constant x frequency
Planck constant = 6.626 x 10^-34 J/s

Spectroscopy

The experimental observation of transitions of molecules between permitted energy levels as a result of absorption or emission of EM radiation

Absorption

Molecule is promoted to a higher energy level as a result of absorption of a photon

Emission / fluorescence

Molecule relaxes to a lower-energy state and emits a photon

spectra

Amount of light absorbed per second

selection rules

Transitions 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 property
Specific selection rules state a restriction on the type of transition.

	Criado por gbslilla mais de 9 anos atrás

Definitions of spectroscopy. 1. lecture for Pharmaceutical Chemistry