Accurate frequency determination of vibration-rotation and rotational
  transitions of SiH+
  The fundamental 28SiH+ ion has been characterized in a collaborative work,
utilizing a hollow-cathode-discharge laser-spectrometer and a cryogenic ion
trap spectrometer. Twenty-three vibration-rotation transitions around 4.75 um
have been detected with high accuracy. This has facilitated the first direct
measurement of the pure rotational transition J=1<-0 at 453056.3632(4) MHz in
the trap spectrometer. The measured and accurately predicted transitions enable
the search for this ion in space with IR and sub-mm telescopes.
