A combination band at 1699.8 cmminus;1for C4trapped in Ar

摘要

An absorption has been detected at 1699.8 cmminus;1in the midinfrared spectrum of the vacuum ultraviolet photolysis products of 1,3hyphen;butadiene (C4H6) trapped in Ar at 10 K, which on the basis of extensive13Chyphen;substitution experiments is shown to belong to the C4carbon chain. The behavior of the new band correlates closely with the ngr;2, Csquflg;C stretching vibration of linear C4at 1543.4 cmminus;1identified in an earlier paper. It is argued that the 1699.8 cmminus;1absorption is a combination band involving the Csquflg;C stretching vibration and a bending mode of C4, with acishyphen;bent structure.