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Analysis of Several High-Resolution Bands of Spiropentane, C5H8



Alfons Weber, A. Maki, J. E. Price, Jared Harzan, J. W. Nibler, T. Masiello, T Blake


The high resolution absorption spectrum of spiropentane (C5H8) from 200 cm-1 to 4000 cm−1 has been measured and a detailed analysis is presented for eight bands in the region from 700 cm−1 to 2200 cm−1. Two fundamental perpendicular bands were analyzed, ν22 and ν24 near 1050 and 780 cm−1 respectively, along with two fundamental parallel bands, ν14 and ν16 near 1540 and 990 cm−1 respectively. A fifth fundamental, ν17 near 880 cm-1, had only P-branch transitions that could be tentatively assigned. In addition, three binary combination bands were fit at about 1570, 2082, and 2098 cm-1 which might be due to either ν5+ν16 or 2ν24 in the first case, ν4+ν22 in the second case, and either ν5+ν14 or ν7+ν11 in the latter case. The two l-type resonance constants, q+ and q−, were determined for the each of the two perpendicular fundamentals ν22 and ν24. Those two constants were also responsible for splittings observed in the K = 3 levels of ν24. For the ground state the order of the split K=2 B1/B2 levels has been reversed from that reported previously, based on the measurements and assignments for the ν24 band. Rovibrational parameters deduced from the analyses are compared with those obtained from density functional Gaussian calculations at the anharmonic level.
Journal of Molecular Spectroscopy


Spiropentane, High-resolution infrared spectrum, Rovibrational constants, DFT study, Anharmonic frequencies


Weber, A. , Maki, A. , Price, J. , Harzan, J. , W., J. , Masiello, T. and Blake, T. (2015), Analysis of Several High-Resolution Bands of Spiropentane, C5H8, Journal of Molecular Spectroscopy, [online], (Accessed April 17, 2024)
Created June 15, 2015, Updated November 10, 2018