In principle yes, but in practice it’s very unlikely—and that’s why nearly all known astrophysical masers come from small, simple molecules.
Why small molecules dominate masers
Most astronomical masers involve species like:
- H₂O
- OH
- SiO
- CH₃OH (methanol)
These work well because:
- They have simple, well-separated energy levels (rotational/vibrational).
- They can achieve population inversion under realistic astrophysical conditions.
- Their transitions fall in the microwave/radio regime, where masers operate efficiently.
- They are abundant and robust in space.
What about long-chain hydrocarbons?
Long-chain hydrocarbons (e.g. things like C₆H₂, HC₉N, or larger organics) do exist in space, and we detect them spectroscopically. But maser action from them is problematic:
1. Energy level complexity
- Large molecules have dense, overlapping rotational spectra.
- This makes it hard to isolate a clean transition that can invert and amplify coherently.
2. Rapid relaxation
- Many internal modes (rotations, bends, torsions) provide lots of ways to lose energy.
- That tends to quench population inversion before amplification builds up.
3. Pumping difficulty
- Masers need a specific pumping mechanism (radiative or collisional).
- For large molecules, it’s much harder to selectively pump one transition without populating many others.
4. Low abundance & fragility
- Long chains are typically less abundant.
- They’re more easily destroyed by UV radiation in star-forming regions (where masers often occur).
Are there exceptions?
- Methanol (CH₃OH) is already a “moderately complex” organic molecule and produces very strong masers.
- Some slightly larger species (e.g. formaldehyde, H₂CO) also mase under certain conditions.
But beyond that size, confirmed astrophysical masers are extremely rare to nonexistent.
Bottom line
You could imagine a long-chain hydrocarbon masing if:
- it had a favorable transition,
- a clean pumping route,
- and the right environment,
…but nature strongly favors small, rigid molecules for sustaining maser action. The bigger and floppier the molecule, the harder it is to keep the inversion alive long enough to get amplification.