Because of their high stability, the presence of diamond-type molecules has long been suspected in the interstellar medium, a hypothesis supported by the extraction of diamond nanocrystal from some meteorites. We report the rotational and vibrational investigation of two polar derivatives of adamantane (C₁₀H₁₆), 1-cyanoadamantane (C₁₀H₁₅–CN) and 1-isocyanoadamantane (C₁₀H₁₅–NC), using room temperature gas phase absorption spectroscopy. Pure rotational spectra have been recorded at millimeter wavelengths (75–220 GHz) while vibrational spectra were obtained in the far- and mid-infrared domains (50–3500 cm⁻¹). Quantum chemical calculations have been performed on these two $C_{3\mathrm{v}}$ rotors to support the spectral analysis enabling the assignment, for both species, of more than 7000 pure rotational transitions in the ground (A₁ symmetry) and first vibrationally excited (E symmetry) states, and of most of the infrared active bands. The pure rotational lines were fit to their experimental accuracy using a symmetric-top Hamiltonian. Our study provides all necessary information for an active search of these species in space.

由于它们的高稳定性，长期以来人们一直怀疑在星际介质中存在钻石型分子，这一假设得到了从某些陨石中提取钻石纳米晶体的支持。我们报告金刚烷的两个极衍生物的转动和振动调查（C ₁₀ H ^ ₁₆），1- cyanoadamantane（C ₁₀ ħ ₁₅ -CN）和1- isocyanoadamantane（C ₁₀ ħ ₁₅ -NC），采用室温下的气相吸收光谱学。在毫米波长（75–220 GHz）处记录了纯旋转光谱，而在远红外和中红外域（50–3500 cm ^-1）获得了振动光谱）。对这两个进行了量子化学计算$C_{3\mathrm{v}}$转子支持光谱分析，可以为这两种物质分配基态（A ₁对称）和第一振动激发（E对称）状态以及大多数红外活动带中的7000多个纯旋转跃迁。使用对称顶部哈密顿量将纯旋转线拟合到其实验精度。我们的研究为主动搜索这些物种提供了所有必要的信息。