Hochauflösende Fourier-Transform-Infrarot-Spektroskopie der dreiatomigen Moleküle HCP, DCP und HBS

Abstract

High Resolution Fourier-Transform-Infrared-Spectroscopy of the triatomic molecules HCP, DCP and HBS

Samples of HCP were synthesized by pyrolysis of CH₃PCl₂. The High Resolution FTIR-Spectra of the bending vibration [ny]₂ and the stretching vibrations [ny]₁ and [ny]₃ of HC¹²P and H¹³CP in ground and excitetd states have been measured in absorption. The measurements were performed in ranges up to 3400 cm^-1 with a Bruker IFS 120 HR interferometer at various resolutions up to 0.0016 cm^-1. Through the analysis of the spectra 29 P,R-branches and 18 Q-branches could be assigned for H¹²CP. For H¹³CP 6 P,R-branches and 4 Q-branches could also be assigned. For the first time an experimental vibrational-rotational analysis of the Fermi-resonance polyads (020)/(001), (030)/(011) and (040)/(021)/(002) could be given. The Fermi-resonance off-diagonal matrix elements for the polyads are presented.
High resolution FT-IR emission mesurements of HCP were performed for the first time for HCP. Spectra were recorded in the range of the bending vibration [ny]₂. HCP was synthesized and heated up to 1400 °C in a high temperature furnace. The products of the pyrolysis were directly measured in the reaction cell.
Spectroscopic constants including Fermi-resonance parameters for H¹²CP and H¹³CP of the effective Hamiltonian for linear molecules are given.

Samples of DCP were synthesized by pyrolysis of CDCl₂PH₂ (deuterodichloromethylphosphane).
D¹³CP was present in natural abundance. High resolution FT-IR spectra were measured with a BRUKER IFS 120 HR Fourier transform spectrometer using a White-type cell with absorption path lengths up to 13.12 m. The wavenumber regions measured were 400 - 600, 600 - 800, 1900 - 2700, 3300 - 4200, 4600 - 5500 and 4500 - 4900 cm^-1 with resolutions of 0.00189, 0.00189, 0.00356, 0.0070, 0.0097 and 0.0167 cm^-1, respectively. In the lowest wavenumber region the [ny]₂ fundamental band, hotbands from [ny]₂ = 1, 2, 3, 4, and [ny]₃ = 1, 2, 4 as well as n1 = 1, 2 and several combination states (v₁v₂^l2v₃) = 011, 110, 012, 210, 014 and 220 were assigned and analyzed.
A complete Fermi-resonance analysis of the following polyads (100)/(002), (110)/(012) and (200)/(004)/(102) could be given. The polyads (022)/(120) and (210)/(014)/(112) were observed partially and the Fermi-resonance analysis was possible approximating one missing level for each polyad. The fundamental and overtone bands of the bending vibration of D¹³CP, and its hotbands from [ny]₂ = 1, 2, as well as the [ny]₁ fundamental and [ny]₃ = 2 band were also assigned and analyzed. The Fermi-resonance analysis of D¹³CP, could be given for the dyad (100)/002).
The bands for D¹²CP observed for the first time in this work are: (004) - (000), (001) - (010), (011) - (020),(011) - (001), (030) - (020), (040) - (030), and for D¹³CP : (010) - (000),(020) - (010), (100) - (000) and (002) - (000). Spectroscopic constants including Fermi-resonance parameters for D¹²CP and D¹³CP of the effective Hamiltonian for linear molecules are given. Through the analysis of the spectra 35 P,R-branches and 19 Q-branches could be assigned for D¹²CP. For D¹³CP 6 P,R-branches and 4 Q-branches could be assigned.

Samples of HBS were synthesized by the reaction of Boron and Sulfur at 1100° C. The High Resolution FT-IR-Spectra of the stretching vibrations [ny]₁ and [ny]₃ of HBS and its isotopomers in ground and excitetd states have been measured in absorption. High resolution spectra were measured with a BRUKER IFS 120 HR Fourier transform spectrometer using a 40 cm long cell. HBS is an unstable molecule, it was produced outside the glastube and pumped trough the measurement aparatus.

High resolution infrared measurements of HBS were also performed using the Giessen diode laser spectrometer (TDL).

All line positions including the calibration data and overview plots of all spectra are given in the addendum.