LITHIUM EMISSION SPECTRUM PLUS
LITHIUM EMISSION SPECTRUM SERIES

When electromagnetic radiation passes through a material, a part of the electromagnetic radiation may be absorbed. However, when atoms in their elemental form are heated or excited, the line spectra that originate are known as the atomic spectra. We know that when elements or their compounds are heated, they release energy in the form of light, which gives rise to a line spectrum. Due to the availability of multiple states of energy, an electron can undergo numerous transitions, each giving rise to a unique wavelength that comprises the emission spectrum. When the electron falls back to the lower energy level, light is emitted, which has the energy equivalent to the higher and the lower states’ energy difference. When an atom or molecule absorbs energy, the electrons are excited to a higher energy level. An example of an emission spectrum is when copper is heated on a flame, and the flame gets green color. Now let's define the line emission spectrum: a spectroscope splits the emitted light into different wavelengths and gives a discontinuous spectrum in the form of discrete lines known as a line spectrum. So, what is the emission spectrum definition in physics and chemistry? An emission spectrum is the range or array of wavelengths (spectra) obtained when the light emitted by a substance is passed through a prism and examined directly with a spectroscope. The different constituent wavelengths of white light are arranged in the spectrum in a specific order, starting with the longest wavelength (red) and shading through to the shortest ( violet).

LITHIUM EMISSION SPECTRUM SERIES

Whether it is physics or chemistry, the spectrum definition is the same - when white light is passed through a prism or any other dispersing substance, the white light splits into a series of coloured bands or lines known as a spectrum. The same model for the 2p electron suggests only about 0.5% of its time inside the shielding.Before we discuss the emission spectrum definition, let us address the questions - what is a spectrum in chemistry and what is a spectrum in physics. Modeling this situation by dividing the electron's time between perfect shielding and no shielding, the percentage of time inside the shielding is calculated to be about 6% for the 2s electron. If there were no shielding of the 2s electron, it would be exposed to the entire nuclear charge and have energy -30.6 eV. The illustration above uses the hydrogen wavefunctions, which are not exactly correct for lithium but can be used to obtain a qualitative understanding of the dependence of the electron energies on the orbital quantum number. The 2s electron is lowered about 1.7 eV below the n=2 hydrogenic energy level of -3.4 eV which it would have if the shielding were perfect. Both levels penetrate enough to be significantly lower than the n=2 hydrogen energy which they would have if the shielding were perfect. The lithium 2s level is significantly lower than the 2p because of greater penetration past the shielding of the 1s electron. Why do levels vary with orbital quantum number? The ionization potential given by NIST was 5.395 eV. Discrepancies may remain with the other levels.

LITHIUM EMISSION SPECTRUM PLUS

The levels up through the 3d plus the 4p and 4d were rescaled to fit the data in the table of neutral lithium levels from NIST. The general layout here was taken from Rohlf but some discrepancies were found in the lower levels. This is true for high angular momentum states as shown, but the s and p states fall well below the corresponding hydrogen energy levels.

Since the outer electron looks inward at just one net positive charge, it could be expected to have energy levels close to those of hydrogen.

The lithium atom has a closed n=1 shell with two electrons and then one electron outside. Hydrogen-Like Atoms:Lithium Lithium Energy Levels

Lithium emission spectrum