Substituted Methanes. XVIII. Vibrational Spectra of C13H3I

Raman (liquid) and infrared (liquid and gas, with KBr and NaCl prisms) spectra have been obtained for two mixtures of C13H3I (9.3 and 61 atom percent) and C12H3I, and from these the vibrational spectrum of C13H3I has been deduced. In the Raman spectrum, only v3(a1)—the C–I stretching frequency—could be resolved from the C12H3I lines; the isotopic shift was — 17.7±0.5 cm—1. In the infrared spectrum (gas), five isotopic shifts were obtained; they were: v1(a1) — 10±3, v2(a1) — 5.5±1.0, v3(a1) — 16.1±1.0, v5(e) — 4.4±0.8, and v6(e) — 3.7±0.3 cm—1. For the remaining fundamental, v4(e), the shift was obtained by use of the Redlich-Teller product rule; the value was — 9.4±2.3 cm—1. Analysis of the perpendicular bands yielded, with the aid of microwave data, values of the rotational constants, Coriolis interaction constants, and band origins for the v6(e), v5(e), and v4(e) bands of C12H3I and C13H3I, though the values for the v4(e) band of C13H3I are incomplete and are only estimated values since the sub-bands were not resolved in this case.