Atomic Spectra of Hydrogen

When energy is added to the hydrogen atom (e.g., by heating or applying electricity), the electron absorbs this energy and jumps to a higher energy level (denoted by n₂), moving further from the nucleus. This excited state is temporary.

The electron eventually returns to a lower energy level (denoted by n₁), releasing the absorbed energy as electromagnetic radiation. This process results in the emission of specific wavelengths, producing distinct lines in the hydrogen atom’s emission spectrum. These wavelengths can be calculated using the Rydberg formula. Thus, the emission spectra of hydrogen are unique and help in understanding atomic structure.

The hydrogen emission spectrum is divided into different spectral lines based on whether the emission falls in the visible, ultraviolet, or infrared region. These spectral lines are collectively referred to as the Balmer, Lyman, Paschen, and Bracket series. Aside from this, there are Pfund and Humphreys series, but they are not widely studied.

Balmer Series

The Balmer series is the most important part of the hydrogen emission spectrum because it is visible to the naked eye. It consists of light emitted when electrons fall to the second energy level (n₁ = 2) from higher levels (n₂ = 3 → ∞), and hence, collectively forms a series.

The Balmer series includes several bright lines, each corresponding to a specific color and wavelength, such as H-alpha (red, 656 nm), H-beta (green-blue, 486 nm), H-gamma (blue, 434 nm), and H-delta (violet, 410 nm). These transitions provide evidence for the quantized nature of energy levels in atoms.

The Balmer series is used to identify hydrogen in distant stars, as the same transitions occur universally.

Lyman Series

Lyman series occurs when an electron drops to the first energy level (n₁ = 1), emitting light in the ultraviolet region. This series is crucial in astronomy and atomic structure studies, revealing high-energy processes in the universe.

Paschen Series

Paschen series involves transitions to the third energy level (n₁ = 3), emitting light in the infrared region. It is important to study the behavior of electrons in atoms and molecules using infrared detectors.

Brackett Series

Brackett series involves transitions to the fourth energy level (n₁ = 4), also in the infrared region. This series helps in studying the thermal properties of stars and galaxies.