the slide contains: 1.atomic excitation& di-excitation. 2. atomic spectra 3. atomic spectral series 4. spectral series of hydrogen

1. ATOMIC SPECTRA,ATOMIC
EXCITATION AND DI-EXCITATION
SYED MOHSIN ABBAS
PIEAS

2. ATOMIC EXCITATION & DE-EXCITATION
 atomic excitation: a state in which an atom or ion
acquires the necessary energy to promote one or
more of its electrons to electronic states higher in
energy than their ground state.

3. ATOMIC EXCITATION & DE-EXCITATION
 atomic de-excitation: process by which an atom
transfers from an excited electronic state back to the
ground state electronic configuration; often occurs
by emission of a photon

4. All objects emit electromagnetic waves. For solid object, such as the
hot filament of a light bulb, these waves have a continuous range of
wavelengths, some of which are in the visible spectrum. The
continuous range of wavelengths is a result of the entire collection of
atoms that make up the solid.
However, different element emit certain specific wavelength
that are unique to those atoms.

5. Atomic Spectra
The spectrum of frequencies of electromagnetic radiation emitted or absorbed during
transitions of electrons between energy levels within an atom. Each element has a
characteristic spectrum by which it can be recognized
The simplest atomic spectrum is that obtained by examining the light emission from a
low-pressure hydrogen arc by mean of visual spectrometer.
◦ A characteristic series
◦ if colored lines
◦ (the Balmer series) is observed

6. The three groups of lines in the hydrogen spectrum
corresponding to the transition of electrons from higher
energy levels to lover energy levels.

7. ATOMIC SPECTRAL SERIES
Balmer series:
 These arise from the fall of electron down
the quantum levels of the hydrogen atom.
 The electrons are initially promoted to the
excited levels(n>1) by the electrical
discharge, and the Balmer series of lines is
produced by spontaneous emission of
light energy of very characteristics
frequencies or wavelengths.
 As electron return from higher excited
state to the second energy state (n=2)

8. ATOMIC SPECTRAL SERIES
 LYMEN(UV),PESCHEN(IR) & PFUND
SERIES:
 Observation of the emissions outside
the visible range show other line
series in the (UV-the Lymen series)
and
 In the near (IR-Peschen series)
 And
 Far – (IR-Pfund series)
 The energy transmission giving rise to
those spectral emissions.

9. ATOMIC SPECTRAL SERIES
 Atomic absorption spectroscopy results from the
reverse transitions in atoms in which the absorption
of quantum of radiation absorbed results in:
 The promotion of the electron in the atom from
ground state energy level to an upper energy level.

10. SPECTRAL SERIES OF HYDROGEN

11. EMISSION AND ABSORBTION OF PHOTON

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