The Vibrational Spectra of Molecules and Complex Ions in Crystals III. Ammonium Chloride and Deutero‐Ammonium Chloride

摘要: The infra‐red spectra of thin non‐scattering films NH4Cl and ND4Cl were obtained at 28°, −78° −190°C. A convenient low temperature transmission type cell usable for such is described. No indication fine structure due to free rotation the NH4+ ions was found. Instead, evidence presented existence, both above below λ‐point, a torsional lattice mode involving ions. limiting frequencies oscillations observed about 390 280 cm−1 ND4Cl, respectively. These values agree quite well with calculated on basis purely electrostatic potential function. modifications indicate strongly that structures belong space group Td1 in which ion symmetry Td. Of eight bands, two are assigned triply degenerate fundamentals ν3 ν4, one overtone 2ν4, combination ν2+ν4 resonates ν3, combi...