Hope

Here, we aim at describing in detail the procedures we follow in order to perform ab initio calculations on complex manifolds of excited states of lanthanide ions in solid hosts. So we hope to help others to do the same calculations if they find them useful, as we do. We follow a ship's log approach (cuaderno de bitácora): we write in it all the steps we do, so that somebody else can follow the track. Then, the basic document is the cuaderno de bitácora, in brief bitácora (though the bitácora is only the binnacle, where the compass and the ship's log book are stored.)

Why should we care about doing such ab initio calculations? Let us just quote the seminal author G. Blasse (Utrecht University). In his 1997 revision on unsolved basic problems in luminescence of inorganic phosphors "Classical Phosphors: A Pandora's box" [2], he concludes:

"From what has escaped from my Pandora’s box it may be concluded that broad-band luminescence in inorganic systems lacks a quantitative understanding, and in many cases even a qualitative one. After opening it, Pandora closed her box immediately, so that at least the hope remained. This seems also to apply to the present situation. We can have some hope that the information available from ab initio molecular orbital calculations of the ground and excited states is becoming so detailed, that it might be possible to solve the type of problems sketched. However, it should be realized that such type of calculations are by no means easy and will require a years-taking effort."

This message was renovated and strengthen by A. Meijerink in his 2011 paper presented at the 9th Annual Phosphor Global Summit 2011 "Revisiting Pandora's box of luminescence".

We have been working on ab initio calculations on excited states of transition metal ions in solid hosts since 1988, and of lanthanide, actinide and other active dopants since 2001 [3].

By now we hope to have set up calculation standards for the crowded manifolds of local excited states that make these materials interesting. These standards include a balanced and high quality wave-function based description of embedding, dynamic correlation, and relativity up to spin-orbit coupling, in unfilled shells (open-shells) of different natures and with large numbers of states close in energy. This site is a tutorial on how we perform such calculations.

Art works shown: Pandora, J. W. Waterhouse, 1896, and Pandora's box, Andrew Junge, 2005.

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