Fundamental Vibrational Frequencies in Ketene and the Deuteroketenes

Abstract

Accurate microwave relative intensity measurements have been made on rotational transitions of ketene and its deutero derivatives in the ground and first vibrational states. The results allow the three lowest fundamental frequencies of these molecules to be positively determined. For CH2CO these modes are found to be 443, 527, and 617 cm−1. The lowest frequency is nearly 100 cm−1 lower than any fundamental previously cited from infrared data for ketene. To substantiate the microwave results solid-state infrared spectra of the molecules at −192° have been investigated in the region 300–4000 cm−1. The low-frequency spectra are in good agreement with the microwave data, and a complete analysis allows the nine fundamentals of CH2CO, CHDCO, and CD2CO to be evaluated. The three lowest fundamentals of CH2CO in the solid are found at 433, 513, and 613 cm−1. The thermodynamic properties of ketene have been recalculated.

Pyrolysis of phenylmercaptoacetic acid

“…spectrum of a cun~ulative sample of the contents of the trap at -188 "C, collected for several experiments, also revealed a strong absorption at 2150 cm-1, which could be assigned to the -C=C=O asymmetric stretching vibration of ketene (6); the other three smaller absorption peaks of this i.r. spectrum (at 3070, 1388, and 1120cm-1) confirmed further the presence of ketene in this sample (7,8).…”

Infrared Spectrometry

“…Linearity of P-N=C=0 groups in P(NCO)s and PO(NCO)3 could not be established bv a vibrational study (385). Ketene was examined in detail in two studies and reassigned (127,399). Measurement of intensities of microwave lines enabled the three lowest fundamental modes to be determined (127).…”

“…Ketene was examined in detail in two studies and reassigned (127,399). Measurement of intensities of microwave lines enabled the three lowest fundamental modes to be determined (127). Diazomethane (398) and methyl azide (387) assignments also received some more attention, and reassignments were made.…”

Application of a PC-Controlled MW-Spectrometer for the Analysis of Ketene-D2. Simultaneous Analysis of Vibrational Excited States Using Microwave and Infrared Spectra

“…-The last figure has poor significance. Transitions with ** have been measured by Nemes and Winnewisser [7], Transitions with * arc given in [2,3,14]. ties in the preparation were D2C = CD2, DC = CD, D3C -C D = CD2 and (D3C)2CÖ, which could be par tially removed by low temperature distillation.…”

“…Starting values for the prediction of the spectra were low frequency lines measured in [3,14], These lines are labelled with (*) in Tables 5, 6, and 7. Lines in the millimeter range were identified partly through the Stark effect and partly by means of double resonance experiments.…”