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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: aktimane on August 16, 2021, 10:05:06 AM

Title: Can alkaline environments encourage photoionisation?
Post by: aktimane on August 16, 2021, 10:05:06 AM

Basically this is about laser ablation of glass in an alkaline environment, namely different KOH solutions. The glass seems to be easier ionised/ablated in the alkaline solution and i'm really not sure why. Could the presence of KOH somehow make an Ionisation more favorable? from what i've read long exposure actually raises the damage threshhold by etching away surface near damages inside the glass.

i'm kinda stuck with this and starting to question the measurements so i hope someone can help or point me in a direction to research. thanks very much!

Title: Re: Can alkaline environments encourage photoionisation?
Post by: MOTOBALL on September 22, 2021, 11:09:29 AM

Even relatively short exposure of glass to strong bases (e.g., NaOH, KOH) will fuse a ground glass stopper to a ground glass neck of a bottle.
This is because the base actually dissolves the glass.

I suspect that the action of the base may cause the formation of deeper, and more, peaks and valleys on the surface of the glass.
Your laser beam may then actually sample a surface area that is 10, 100 , 1000 etc times larger than on untreated glass.
What order of magnitude increase in signal do your expts give???