Femtosecond laser ablation of solid methane

Solid methane at 77 K was irradiated with laser pulses of wavelength 800 nm and energy of 275 μJ. Laser pulse duration was 100 fs. This irradiation experiment shows formation of higher molecular weight pure carbon clusters C_n where n = 1, 2, 3, …, and the formation of alkane molecules of higher molecular mass than the original target molecule. These molecules have the composition (CH₄)_n where n = 1, 2, 3…. The time of flight spectrum also shows the formation of polyynes and cumulenes as ablation products.