Precision spectroscopy of non-thermal molecular plasmas using mid-infrared optical frequency comb Fourier transform spectroscopyThe dataset contains results from application of a mid-infrared frequency comb-based Fourier transform spectrometer to measure high-resolution spectra of plasmas containing hydrogen, nitrogen, and a carbon source in the 2800 – 3400 cm–1 range. The spectrally broadband and high-resolution capabilities of this technique enable quantum-state-resolved spectroscopy of multiple plasma-generated species simultaneously, including CH4, C2H2, C2H6, NH3, and HCN, providing detailed information beyond the limitations of current methods. Using a line-by-line fitting approach, we analyzed 548 resolved transitions across five vibrational bands of plasma-generated HCN. The results indicate a significant non-thermal distribution of the populations among the quantum states, with distinct temperatures observed for lower and higher rotational quantum numbers, with a temperature difference of about 62 K. Broadband state-resolved-spectroscopy via comb-based methods provides unprecedented fundamental insights into the non-thermal nature of molecular plasmas – a detailed picture that has never been accomplished before for such complex non-thermal environment.

]]>comb spectroscopyquantum-state-resolved spectroscopyPlasma Chemical Processes97aea672-436e-44e7-a86f-e95a99f3bf282024-07-15T22:27:08+02:002024-07-15T22:27:17+02:00enINP, Nicolaus Copernicus UniversityPrecision spectroscopy of non-thermal molecular plasmas - Fig. 2Measured high-resolution spectra of a plasma nitrocarburizing. The x-axis is wavenumber (in cm⁻¹) and the y-axis is absorption. Measurement conditions: Pulsed DC discharge of 1 kHz and a duty cycle of 60 %; process pressure of 3 mbar; Plasma power = 26 W, Process pressure = 3 mbar; Precursor gases: N₂ and H₂ with mass flow rates of 10 cm³ min⁻¹ at standard conditions. An active screen of CFC was used as a source of carbon.

]]>2024-07-13T22:17:00+02:002024-07-15T22:25:57+02:00text/csvcsv6731088https://inptdat.de/dataset/precision-spectroscopy-non-thermal-molecular-plasmas-using-mid-infrared-optical-frequency-0Precision spectroscopy of non-thermal molecular plasmas - Fig. 3Evaluated rotational populations used to create Boltzmann plot for the 0110 hot band vibration of plasma-generated H¹²C¹⁴N at a plasma power of 130 W. The x-axis is lower state energy (in cm⁻¹) and the y-axis is the logarithm of the rotational populations, ni normalized to the statistical weight of the state, gi [ln(ni/gi)].

]]>2024-07-13T22:30:03+02:002024-07-15T22:25:57+02:00text/csvcsv875166https://inptdat.de/dataset/precision-spectroscopy-non-thermal-molecular-plasmas-using-mid-infrared-optical-frequency-1Precision spectroscopy of non-thermal molecular plasmas - Fig. 4aMeasured rotational populations, ni (in cm⁻³) as a function of rotational quantum number, J for the four vibrational states: (i) the 00⁰0-state corresponding to the fundamental ν₁ ← ν₀ band, (ii) the 01¹0-state corresponding to the ν₁+ ν₂ ← ν₂ hot band, (iii) the 02⁰0-state corresponding to the ν₁+ 2ν₂ ← 2ν₂ hot band, and (iv) the 02²0-state corresponding to the ν₁+ 2ν₂ ← 2ν₂ hot band.

]]>2024-07-13T22:37:19+02:002024-07-15T22:25:57+02:00text/csvcsv2999https://inptdat.de/dataset/precision-spectroscopy-non-thermal-molecular-plasmas-using-mid-infrared-optical-frequency-2Precision spectroscopy of non-thermal molecular plasmas - Fig. 4bRotational populations, ni in cm⁻³ of the 01¹0 state as a function of rotational quantum number, scaled to match measured populations of the states 00⁰0, 02⁰0, and 02²0.

]]>2024-07-13T22:46:30+02:002024-07-15T22:25:57+02:00text/csvcsv5547https://inptdat.de/dataset/precision-spectroscopy-non-thermal-molecular-plasmas-using-mid-infrared-optical-frequency-3Precision spectroscopy of non-thermal molecular plasmas - Fig. 5Measured high-resolution spectra of a plasma nitrocarburizing. The x-axis is wavenumber (in cm⁻¹) and the y-axis is transmission. Measurement conditions: Pulsed DC discharge of 1 kHz and a duty cycle of 60 %, process pressure of 3 mbar; Plasma power = 93 W, Process pressure = 3 mbar; Precursor gases: N₂ and H₂ with mass flow rates of 10 cm³ min⁻¹ at standard conditions. An active screen of CFC was used as a source of carbon.

]]>2024-07-13T22:49:12+02:002024-07-15T22:25:57+02:00text/csvcsv2689956https://inptdat.de/dataset/precision-spectroscopy-non-thermal-molecular-plasmas-using-mid-infrared-optical-frequency-4DKANhttps://inptdat.de