One reasonable and memorable approximation excluding any fine structure is:
see for example example: hydrogen 1-2 spectral line.
Equation 21. Hydrogen spectral series mnemonic
- Hydrogen emission spectrum | 0, 117, 2
- Spectral line | 165, 1k, 10
- Emission spectrum | 0, 1k, 11
- Quantum mechanics experiments | 36, 2k, 26
- Quantum mechanics | 170, 18k, 245
- Particle physics | 137, 28k, 449
- Physics | 276, 39k, 680
- Natural science | 0, 48k, 1k
- Science | 0, 52k, 1k
- Ciro Santilli's Homepage | 262, 181k, 3k