Vapour phase Raman spectra of the molecules MH4(M = C, Si, Ge or Sn) and MF4(M = C, Si or Ge). Raman band intensities, bond polarisability derivatives and bond anisotropies

摘要: The vapour phase Raman spectra of the molecules MH4(M = C, Si Ge or Sn) and MF4(M Ge) have been recorded with 488.0 and/or 514.5 nm excitation at pressures 0.5–1.0 atm temperatures ca. 295 K. intensities all four Raman-active fundamentals each molecule determined relative to that ν1(a1) band methane as external standard, this has permitted calculation scattering cross sections for band. Molecular (′j) bond (′MX) polarisability derivatives calculated. ′MH values are similar, a given M atom, ′MF follow trends established previously other ligands (X), ′CX≈′SiX < ′GeX ′SnX. Bond anisotropies (γMX) deduced from ν2(e) fundamental molecule. This method only yields modulus γMX value, but, when taken in conjunction Kerr effect results, it is concluded positive case. Quadratic force fields on assumption Wolkenstein intensity theory, mean square amplitudes vibration also