Calcium monohydride

Calcium monohydride is a molecule composed of calcium and hydrogen with formula CaH. It can be found in stars as a gas formed when calcium atoms are present with hydrogen atoms. Calcium monohydride is a molecule composed of calcium and hydrogen with formula CaH. It can be found in stars as a gas formed when calcium atoms are present with hydrogen atoms. Calcium monohydride was first discovered when its spectrum was observed in Alpha Herculis and ο Ceti by Alfred Fowler in 1907. It was observed in sunspots the following year by C. M. Olmsted. Next, it was made in a laboratory in 1909 by A. Eagle, and with early research by Hulthèn, and Watson and Weber in 1935. It was further observed in M dwarfs by Y. Öhman in 1934. Öhman proposed its use as a proxy for stellar luminosity, similar to magnesium monohydride (MgH), in being more apparent in the spectra of compact, cool, high surface gravity stars such as M dwarfs than in cool, low surface gravity stars such as M giants of non-negligible, or even comparable, metallicity. Calcium monohydride is the first molecular gas that was cooled by a cold buffer gas and then trapped by a magnetic field. This extends the study of trapped cold atoms such as rubidium to molecules. Calcium monohydride can be formed by exposing metallic calcium to an electric discharge in a hydrogen atmosphere above 750 °C. Below this temperature the hydrogen is absorbed to form calcium hydride. Calcium monohydride can be formed by laser ablation of calcium dihydride in a helium atmosphere.