We first present quantitative, broadband absorbance cross sections of the C=O stretch fundamental rovibrational band of methyl formate in the 1670–1850 cm range at temperatures of 300, 600, 800, and 1000 K and pressures of 1–2 atm. The title molecular spectra were additionally studied across the pressure range of 1 to 35 atm at room temperature. Elevated temperature measurements were taken in argon bath gas behind the reflected shock wave of a shock tube by a rapid-tuning, broad-scan external cavity quantum cascade laser. The room temperature cross section of methyl formate was collected to validate our method and agreed well with previous room-temperature measurements by Sharpe et al. Then, to extend the utility of the collected data across intermediate temperatures, a pseudo-line-list (PLL) absorbance model was generated through a simultaneous fit of line-by-line intensities and lower-state energies to the measured cross sections. This PLL model was able to replicate the measurements within 3% across most of the spectral range and within 8% around the extremely sharp Q-branch feature present at room temperature. Cross-validation was then performed by re-fitting the PLL excluding the 800 K data set and demonstrated that the PLL approach is effective in interpolating between measured absorption cross sections at discrete temperatures. Finally, the additional room-temperature measurements from 1 to 35 atm were collected in a high-pressure static cell in nitrogen bath gas. These measurements revealed a notable Q-branch cross section pressure dependence while the P- and R-branch wings remained largely pressure independent across this wide pressure range. The collected methyl formate cross sections comprise the latest addition to the Stanford ShockGas-IR database for mid-infrared polyatomic absorption cross sections at elevated temperatures.

中文翻译：

---

实验温度和压力相关的吸光度截面和甲酸甲酯在[公式省略]附近的伪线列表模型


我们首先展示了在 300、600、800 和 1000 K 的温度和 1-2 atm 的压力下，甲酸甲酯在 1670-1850 cm 范围内的 C=O 伸缩基本振动带的定量宽带吸光度截面。另外在室温下 1 至 35 个大气压的压力范围内研究了标题分子光谱。通过快速调谐、宽扫描外腔量子级联激光器，在激波管反射激波后面的氩浴气体中进行高温测量。收集甲酸甲酯的室温横截面以验证我们的方法，并且与 Sharpe 等人之前的室温测量结果非常一致。然后，为了扩展所收集数据在中间温度范围内的效用，通过将逐行强度和较低态能量同时拟合到测量的横截面，生成了伪线列表（PLL）吸光度模型。该 PLL 模型能够在大部分光谱范围内重复 3% 以内的测量结果，并在室温下存在的极其尖锐的 Q 分支特征周围重复 8% 以内的测量结果。然后通过重新拟合 PLL（排除 800 K 数据集）进行交叉验证，并证明 PLL 方法在离散温度下测量的吸收截面之间进行插值是有效的。最后，在氮气浴气体的高压静态单元中收集 1 至 35 atm 的额外室温测量值。这些测量揭示了显着的 Q 分支横截面压力依赖性，而 P 分支翼和 R 分支翼在如此宽的压力范围内基本上保持与压力无关。 收集到的甲酸甲酯截面包括斯坦福 ShockGas-IR 数据库中最新添加的高温下中红外多原子吸收截面。