Experimental and quantum-chemical characterization of heavy carbon subchalcogenides: Infrared detection of SeC3Se

High-resolution infrared studies of laser ablation products from carbon-selenium targets have revealed a new vibrational band at 2057 cm−1 that is identified as the ν3 fundamental SeC3Se cluster. Because rich isotopic composition selenium and heavy nuclear masses involved, shows relatively compact complex structure despite simple linear geometric arrangement. Overall, rotational-vibrational lines six isotopologues could be assigned fitted permitting derivation an accurate selenium-carbon bond length. Spectroscopic analysis has been greatly supported by high-level quantum-chemical calculations molecular harmonic anharmonic force fields performed CCSD(T) level theory. Scalar-relativistic effects on were also considered but found little importance.