Jyoti,JyotiChakraborty, A.A.ChakrabortyYu, Yan MeiYan MeiYuChen, JingbiaoJingbiaoChenArora, BindiyaBindiyaAroraSahoo, B. K.B. K.Sahoo2025-08-312025-08-312023-08-0110.1103/PhysRevA.108.0231152-s2.0-85167946059https://d8.irins.org/handle/IITG2025/26709We demonstrate that the transition between the fine-structure splitting of the ground state of triply ionized zirconium (Zr iv) is suitable for a terahertz (THz) atomic clock. Its transition frequency is about 37.52 THz and is mainly guided by the magnetic dipole (M1) transition, and it is accessible by a readily available laser. We suggest considering stable even isotopes of Zr and MJ=±1/2 sublevels (i.e., |4D3/2,MJ=±1/2)→|4D5/2,MJ=±1/2) clock transition) for experimental advantage. By performing necessary calculations, we estimate possible systematics due to blackbody radiation and ac Stark, electric quadrupole, and second-order Zeeman shifts along with shifts due to the second-order Doppler effects. The proposed THz atomic clock could be very useful in quantum thermometry and frequency metrology.falseArticle24699934August 20232023115arJournal2