Who is Meghnad Saha?

Meghnad Saha was a renowned Indian astrophysicist who developed the ionisation theory, explaining stellar spectra’ origin. Meghnad Saha rose from humble beginnings in a small village to become one of the world’s most renowned scientists of his time. He struggled to get a primary education because he was born into a low-income family. He graduated with honours from college and landed a job at the University College of Science in Calcutta. He began his research without access to a well-equipped laboratory or a research guide. Nonetheless, he proposed the Saha ionisation equation, which can be used to identify the chemical and physical conditions in stars.

Meghnad Saha’s Career Achievements

In 1917, the University College of Science in Kolkata appointed Meghnad Saha as a professor. He taught quantum physics there. He presided over the Indian Science Congress in 1934. Meghnad Saha was also the chairman of the calendar reform committee established by the Government of India. In 1947, he founded the Institute of Nuclear Physics, later renamed the “Saha Institute of Nuclear Physics.” Saha also used a device to determine the weight and pressure of solar rays. He invented and assisted in constructing several scientific institutions, including the Department of Physics at Allahabad University and the Institute of Atomic Physics in Calcutta.

Meghnad Saha’s Contribution to Astrophysics

When Meghnad Saha was making inventions in astronomy and Physics, he studied subjects such as thermo relativity, dynamics, and automatic theory in-depth, while making many discoveries for solving problems in Astrophysics. He later became famous worldwide for his findings.

Astronomers have used the Saha ionisation equation to determine the internal chemical and physical conditions in stars.

Meghnad Saha’s contribution was not limited to physics and astronomy; he also participated in the Bahot freedom campaign. He wished to give India a highly respected identity in the eyes of the world. His remarkable contribution will never be forgotten.

What Is the Saha Ionisation Equation?

The Saha ionisation equation, also called the Saha-Langmuir equation, was created in 1920 by Indian astrophysicist Meghnad Saha and later (1923) by Irving Langmuir. One of the equation’s most essential applications was describing the spectroscopic conditions of the stars. The equation is the combined concept of statistical mechanics and quantum physics. Thermal collisions of atoms in a gas at a very high temperature will ionise some atoms. More than one charged particle generally revolves around the atomic nucleus in atoms, which are ejected and form a gaseous electron that coexists with the gaseous atomic ions and neutral atoms. This is referred to as a plasma state of matter. The Saha ionisation equation describes the ionisation degree of this plasma as a function of temperature, density, and atom ionisation energies. The Saha ionisation equation is valid only for weakly ionised plasmas with a considerable Debye length.

This implies that the “screening” of ions’ and electrons’ coulomb charges by other ions and electrons is minimal. As a result, the subsequent decrease in ionisation possibilities and the “cutoff” of the dispersion relation is negligible.

The Saha ionisation equation is written to denote a gaseous atom made up of a single atomic ion where:

•  denotes the density of the atoms in the i-th state of ionisation, I electrons removed

•  is the state degeneracy for i-ions

•  is the amount of energy required to remove 1 electron from a neutral atom and produce an i-level ion

•  is the density of an electron.

•   is an electron’s thermal de Broglie wavelength

•  is the electron’s mass

•  is the gas temperature.

•  is Planck’s constant

When only 1 level of ionisation is essential, we have n1 = ne, and when the total density is defined as n = n0 n1, the Saha ionisation equation simplifies to:

The Saha ionisation equation can calculate the particle density ratio for two seperate ionisation levels. For this purpose, the most helpful form of the Saha equation is where Z stands for the partition function. The equation can be considered a revised statement of the chemical potentials’ equilibrium condition.

The Saha ionisation equation implies that the potential for an atom in ionisation stage I to ionise will remain the same as the potential for an atom and electron in ionisation state i 1 to ionise; because potentials are equal, now the system is in equilibrium, and no net change in ionisation will occur.

Conclusion 

India’s most outstanding scientist Meghnad Saha died of a heart attack on February 16, 1956, while attending a job interview at the Scientific Planning Commission at Rashtrapati Bhavan. Meghnad Saha is no longer with us, but in the world of physics, he will be recognised for his unbelievable discoveries in astronomy. Meghnad Saha has received numerous honours for his significant contributions to astronomy. He was elected to the Royal Asiatic Society of London’s Fellowship. Meghnad Saha was appointed to take precedence over the Indian Science Congress in 1934 due to his extraordinary imagination. The government of India established a calendar reform committee chaired by Meghnad Saha.