We use a Fourier transform spectrometer based on a difference frequency generation optical frequency comb to measure high-resolution, low-pressure, room-temperature spectra of methane in the 1250 – 1380-cm⁻¹ range. From these spectra, we retrieve line positions and intensities of 678 lines of two isotopologues: 157 lines from the ¹²CH₄ ν₄ fundamental band, 131 lines from the ¹³CH₄ ν₄ fundamental band, as well as 390 lines from two ¹²CH₄ hot bands, ν₂ + ν₄ – ν₂ and 2ν₄ – ν₄. For another 165 lines from the ¹²CH₄ ν₄ fundamental band we retrieve line positions only. The uncertainties of the line positions range from 0.19 to 2.3 MHz, and their median value is reduced by a factor of 18 and 59 compared to the previously available data for the ¹²CH₄ fundamental and hot bands, respectively, obtained from conventional FTIR absorption measurements. The new line positions are included in the global models of the spectrum of both methane isotopologues, and the fit residuals are reduced by a factor of 8 compared to previous absorption data, and 20 compared to emission data. The experimental line intensities have relative uncertainties in the range of 1.5 – 7.7%, similar to those in the previously available data; 235 new ¹²CH₄ line intensities are included in the global model.

^{我们使用基于差频生成光学频率梳的傅里叶变换光谱仪来测量 1250 – 1380-cm -1}范围内的高分辨率、低压、室温甲烷光谱。从这些光谱中，我们检索了两个同位素体的 678 条线的线位置和强度：¹² CH ₄ ν ₄基带中的 157 条线，¹³ CH ₄ ν ₄基带中的 131 条线，以及两个¹² CH中的 390 条线_{4 个}热波段，ν ₂  + ν ₄ – ν ₂和 2ν ₄ – ν ₄. ^{对于来自12} CH ₄ ν ₄基带的另外 165 条线，我们仅检索线位置。^{线路位置的不确定性范围从 0.19 到 2.3 MHz，与先前可用的12} CH ₄数据相比，它们的中值降低了 18 和 59 倍分别从传统的 FTIR 吸收测量中获得的基本波段和热波段。新的线位置包含在两种甲烷同位素体光谱的全局模型中，与之前的吸收数据相比，拟合残差减少了 8 倍，与排放数据相比减少了 20 倍。实验线强度的相对不确定性在 1.5-7.7% 的范围内，与之前可用的数据相似；全局模型中包含235 个新的¹² CH _{4线强度。}