High-resolution spectroscopy of Holmium Perchlorate: Establishment of wavelength standard for spectrophotometer

We have investigated the excited state dynamics of Holmium Oxide (Ho2O3) dissolved in perchloric acid using ultrafast optical pump-probe spectroscopy by exciting the samples with laser light at 350 nm and 550 nm and detecting in the visible region. Using an ultrafast spectroscopic approach, the stability of Ho2O3 solution has been examined. UV–Visible spectroscopy revealed 14 bands in the Ho2O3 absorption spectrum and by using ultrafast transient absorption spectroscopy, we have probed the dynamics of the excited state and studied transient absorption lifetime in the visible range. We obtained multi-exponential dynamics of carrier relaxation for Ho2O3, with time constants spanning from 0.07 to >500 ps. The lifetime of molecules has been shown to be on the order of picoseconds (ps), proving the stability of Ho2O3 solution and making it suitable for use as a wavelength standard for spectrophotometer calibration.