High-resolution infrared spectrum of cyanogen

The high-resolution spectrum of cyanogen ((14)N(12)C(12)C(14)N) has been measured from 500 to 4900 cm(-1). For this isotopomer many combination levels with both degenerate fundamentals, v(4) and v(5), have been measured for the first time and the effects of vibrational l-type resonance are observed as well as rotational l-type resonance. The effects of the vibrational resonance coupling v(2) and 2v(4) have also been studied. The data have been combined with earlier measurements below 500 cm(-1) to give a comprehensive catalog of the vibrational energy levels and the rovibrational constants for the normal isotopomer of cyanogen. A comparison of the term value constants for the three major symmetric isotopomers is given and they are compared with a recent ab initio calculation. The present data were combined with earlier work on the two symmetric isotopomers. (13)C(2)(14)N(2) and (12)C(2)(15)N(2), to obtain the equilibrium bond lengths, r(CC) = 138.109(60) pm and r(CN) = 115.976(40) pm. (C) 2011 Elsevier Inc. All rights reserved.