Methane as a reddish coating agent

TY - JOUR

T1 - Methane as a reddish coating agent

AU - Nørnberg, Per

AU - Finster, Kai

AU - Thøgersen, Jan

AU - Golbek, Thaddeus W.

AU - Weidner, Tobias

AU - Hassenkam, Tue

AU - Goetz, Walter

AU - Oehlke, Mathias

AU - Knak Jensen, Svend J.

N1 - Publisher Copyright: © 2022 The Authors

PY - 2022/8

Y1 - 2022/8

N2 - Experiments in quartz ampoules that simulate the saltation of quartz grains in a methane atmosphere show that the solid phase acquires a reddish color, reminiscent of the color observed on Triton, Pluto, and Charon. Reflection spectroscopy of the coated grains show a wide, continuous absorption spectrum peaking at near-UV wavelengths, in line with the reddish color. X-ray photoelectron spectroscopy indicates the grains are coated with a substance containing C–C and C–O bonds, and estimates the average thickness of the surface layer to 2.3 Å. Solid state Raman measurements of the coating shows a transition at 1540 cm−1. A model is proposed to describe these measurements. The model is a polydiene, anchored to the quartz surface. Electron structure calculations show that a polydiene with around 8 CH units reproduces the measurements. AFM-IR experiments support this result. Our findings suggest a pathway for synthesis of complex molecules with C[dbnd]C bonds on planets and moons with a solid surface and a methane-containing atmosphere.

AB - Experiments in quartz ampoules that simulate the saltation of quartz grains in a methane atmosphere show that the solid phase acquires a reddish color, reminiscent of the color observed on Triton, Pluto, and Charon. Reflection spectroscopy of the coated grains show a wide, continuous absorption spectrum peaking at near-UV wavelengths, in line with the reddish color. X-ray photoelectron spectroscopy indicates the grains are coated with a substance containing C–C and C–O bonds, and estimates the average thickness of the surface layer to 2.3 Å. Solid state Raman measurements of the coating shows a transition at 1540 cm−1. A model is proposed to describe these measurements. The model is a polydiene, anchored to the quartz surface. Electron structure calculations show that a polydiene with around 8 CH units reproduces the measurements. AFM-IR experiments support this result. Our findings suggest a pathway for synthesis of complex molecules with C[dbnd]C bonds on planets and moons with a solid surface and a methane-containing atmosphere.

KW - Atmospheres

KW - Chemistry

KW - Prebiotic chemistry

KW - Satellites

KW - Spectroscopy

KW - Surfaces

UR - http://www.scopus.com/inward/record.url?scp=85129326722&partnerID=8YFLogxK

U2 - 10.1016/j.icarus.2022.115023

DO - 10.1016/j.icarus.2022.115023

M3 - Journal article

AN - SCOPUS:85129326722

SN - 0019-1035

VL - 382

JO - Icarus

JF - Icarus

M1 - 115023

ER -