Water Molecule Oscillation Modes and Photodissociation
August 5th, 2008I’ve been kind of busy with real life again in the last few days so I haven’t has as much time to research or write for the blog lately. However, I have got some interesting results from a little water research I was able to do.
I discovered that the most efficient way to break the Hydrogen and Oxygen bonds in the water molecule is actually with light, this process is called Photodissociation. This is actually happening all around us all the time, it is the process known as photosynthesis and it happens in plants every time the sun comes out and hits green plants. The sun light enters into the plant cell and some of these light rays hit Chlorophyll molecules. “The chlorophyll donates an electron into a series of molecular intermediates called an electron transport chain.”
http://en.wikipedia.org/wiki/Chlorophyll
Basically the light energy is transfered through electron doners down a chain of complex protines. The energy eventually participates in a complex biochemical reaction that breaks CO2 and 2H2O releasing 2O2, and using the remaining atoms to form cellular structures that are used to build additional protines, cells and cell structures. Thus the plant grows and consumes CO2 from the air releasing O2 for the rest of us to breath! All this talk of scrubbing CO2 from the air, and you would think that people would have consider to use what nature already does best with sunlight. But NOOO us humans are gready and this process isn’t fast enough for us! We want it on an industrial scale!!! Note: Carbon-Hydrogen chains comprise the bulk of our oil needs, otherwise known as fossil fuels taken from decayed plant matter that has thus formed into oil.
So I did some more research into the absorbtion spectra of water, and I found that water has a STRONG photo absorbition below 100nm. nm stands for Nano Meters, or one billionth of a meter:
http://en.wikipedia.org/wiki/Nanometer
So this puts light absorbition for water at the strongest into the deep UV range, which is why so many harmful UV rays are blocked out from the sun by our thick atmosphere around the Earth. Much of our atmosphere contains a great deal of water vapor, this does the job at blocking a good deal of the UV radiation coming from the sun. The absorbtion wave lengths are at their minimum at the green and blue spectrum of visible light. This might have something to do with why our plants are all green. At the red end of the visible spectrum the absorbtion of light into the water molecule is many times greater. Absorbtion has several minor peaks in the infrared reaching a maximum at around 1000nm.
http://people.seas.harvard.edu/~jones/es151/gallery/images/absorp_water.html
I dug a little deeper and discovered that different wave lengths contribute to different oscillation modes within the water molecule. I found that there has been plenty of research into the water molecule using X-ray spectroscopy and neutron diffraction. I discovered that there are 6 major different types of oscillation modes in the water molecule, and some of these vibrational models contribute to thermal heating of water more then other oscillation modes.
First of all, if you don’t know what the water molecule looks like, then I suggest you find out:
http://en.wikipedia.org/wiki/Water
I learned that the Hydrogen atoms can oscillate away from the oxygen atom in a symetric stretching of the Van Der Waals Hydrogen bonding length, or a similar stretching of the bond length in asymmetric stretching. These are known as V1 and V3.
V2 oscillation is a bending of the bond angle between the hydrogen atoms.
Additionally the water molecule can spin on 3 different axis, one axis bisecting the Hydrogen bond angle but in the same plane as the Hydrogen atoms, the other axis being perpendicular to the previous and also in the same plane as the Hydrogen atoms, and the 3rd axis being through the Oxygen atom but perpendicular to the plane of the Hydrogen Atoms. These last three spinning oscillations contributing much more to a thermal energy increase in the water. That is to say these last three oscillations increase the temperature of the water. The first three oscillation modes do also contribute to the thermal energy of the water although not nearly as much.
So it does stand to reason that it may just be possible to aid in the stretching and instability of the Hydrogen-Oxygen bonding in the water molecule by inducing these oscillation modes. I believe this is called increasing the bonding stress in the water molecule.
I also found that light wavelengths below 500nm contribute mostly to V1 and V3 oscillations. Light wavelengths around 836nm contribute to V1, V2 and V3 oscillations. Light wavelengths around 1000nm contribute to V1 and V3 oscillations.
http://www.lsbu.ac.uk/water/vibrat.html
Apparently it is almost impossible to find a light source around 100nm, usually this is in the medical field, and rather expensive. Typically used in water purification pens with deep UV light.
It is however easy to find 1000nm Infrared laser diodes or LED’s for VERY cheep!!!
According to a source I listed in a previous HHO post:
http://www.nature.com/nature/journal/v454/n7200/full/nature07079.html
This suggests to me that it is entirely possible to use light as an additional technique in optimizing the energy needed to break the Hydrogen-Oxygen bonds of the water molecule. Just something to consider when your building your next HHO unit.
Enjoy
~Seth