Diode laser spectroscopy of 10B16O and 11B16O boron monoxide (<f>X</f><f>2Σ+</f>)

The absorption spectra of the fundamental bands of the free radicals 10B16O and 11B16O in their ground <f>2Σ+</f> states have been measured in natural abundance and at Doppler limited resolution using diode laser spectroscopy. The band origins are found to be 1915.30674(14) and 1861.92409(13) cm−1, respectively. The rotational constants for the lower states are 1.877680(22) and 1.773421(10) cm−1, which are in excellent agreement with the microwave values for <f>B0</f>. Assuming a linear dependence of <f>Bv</f> on (<f>v+1/2</f>) the derived value of <f>re</f> is 1.204552(5) A˚. [Copyright &y& Elsevier]