Attainable accuracies of QH+ rotational transition frequencies (Q: 40Ca, 24Mg, 202Hg)

Molecular rotational transition frequencies are useful as frequency standard in the terahertz region. The transition frequencies of QH+ molecular ions (Q: an even isotope of Group II element) in a linear trap are useful as measurement uncertainties are low. An uncertainty given by the Stark and Zeeman shifts can be below 10−15 using 202HgH+ molecular ion.