The Rydberg constant sets the wavelengths of hydrogen's spectral lines. Times hc it gives 13.6 eV, the energy to ionise hydrogen from the ground state.
Value of R in different units
| Value | Use it when |
|---|---|
| 1.097 × 10⁷ m⁻¹ | R∞, the usual value in physics. |
| 1.09677 × 10⁷ m⁻¹ | R_H for hydrogen, with the reduced-mass correction. |
| 109 677 cm⁻¹ | Chemistry books (R_H in wave numbers). |
| 13.6 eV (Rhc) | Ionisation energy of hydrogen. |
| 2.18 × 10⁻¹⁸ J (Rhc) | Same energy in joules. |
Formulas that use R
- 1/λ = RZ²(1/n₁² − 1/n₂²)
- Eₙ = −13.6 Z²/n² eV
Its dimensional formula is worked out on the dimensional formula of rydberg constant page.
Other constants
- Gas constant (R): 8.314 J mol⁻¹ K⁻¹
- Planck's constant (h): 6.626 × 10⁻³⁴ J s
- Avogadro's number (Nₐ): 6.022 × 10²³ mol⁻¹
- Speed of light (c): 3 × 10⁸ m/s
- Charge of an electron (e): 1.602 × 10⁻¹⁹ C
- Mass of an electron (mₑ): 9.109 × 10⁻³¹ kg
- Mass of a proton (mₚ): 1.673 × 10⁻²⁷ kg
- Mass of a neutron (mₙ): 1.675 × 10⁻²⁷ kg
- Universal gravitational constant (G): 6.674 × 10⁻¹¹ N m² kg⁻²
- Acceleration due to gravity (g): 9.8 m/s²
- Boltzmann constant (k): 1.381 × 10⁻²³ J/K
- Faraday constant (F): 96 485 C/mol
- Permittivity of free space (ε₀): 8.854 × 10⁻¹² C² N⁻¹ m⁻²
- Permeability of free space (μ₀): 4π × 10⁻⁷ T m/A
- Rydberg constant (R): 1.097 × 10⁷ m⁻¹
- Stefan–Boltzmann constant (σ): 5.67 × 10⁻⁸ W m⁻² K⁻⁴
- Wien's constant (b): 2.898 × 10⁻³ m K
- Bohr radius (a₀): 0.529 Å
- Molar volume of a gas at STP (Vₘ): 22.4 L/mol
The full list, searchable, is on the physical constants page.
Questions students ask
What is the value of Rydberg constant?
R = 1.097 × 10⁷ m⁻¹. In other units: 1.097 × 10⁷ m⁻¹; 1.09677 × 10⁷ m⁻¹; 109 677 cm⁻¹; 13.6 eV (Rhc); 2.18 × 10⁻¹⁸ J (Rhc).
What is R in physics and chemistry?
The Rydberg constant sets the wavelengths of hydrogen's spectral lines. Times hc it gives 13.6 eV, the energy to ionise hydrogen from the ground state.
Which value of R should I use?
1.097 × 10⁷ m⁻¹: R∞, the usual value in physics. 1.09677 × 10⁷ m⁻¹: R_H for hydrogen, with the reduced-mass correction. 109 677 cm⁻¹: Chemistry books (R_H in wave numbers). 13.6 eV (Rhc): Ionisation energy of hydrogen. 2.18 × 10⁻¹⁸ J (Rhc): Same energy in joules.
What is the dimensional formula of Rydberg constant?
See the dimensional formula of Rydberg constant, worked out step by step on its own page.