Work Function and Lattice Energy

Subject: Fwd: [AIAS] Fwd: Work Function and Lattice Energy
Date: Thu, 28 Jun 2007 10:59:35 EDT

Thanks Myron, will do my best to contribute. The work function is of course lower than the ionisation energy. So for Caesium, for example, the ionisation energy (from a quick search) is 3.9eV

Cs(g) —> Cs+(g) +e- 3.9eV

whereas the work function is only 1.9eV

Best, Gareth

–Forwarded Message Attachment– I can invite you to be a co-author of paper 87 with Horst and myself, a paper in which the work function discussion would be developed and included. This is another key step. SCR has now been published un Europe, which is now the power house of theoretical physics (we again see this objectively from feedback activity).

–Forwarded Message Attachment–

Yes Myron, we are getting close to designing a first device based directly on your theory. At the moment I see a device based on a sandwich of materials with the key material to be “excited” (release electrons) at the centre of the sandwich. Best, Gareth

This is a very good discussion. It looks as if we should find the material with the lowest work function in the solid state, and use that in the circuit of paper 63 and improvements which may come out of paper 87 being worked on at present, also using a literature search of circuits by Tesla and other inventors as a guide. Density functional code should be able to produce the work function of solids from quantum mechanics, then the effect of the amplified Lamb shift is computed to see what is the effect on the material with the lowest work function. The Lamb shift is the driving force and resonant amplification of the radaitive correction occurs through the spin connection of unified field theory. This is a useful table and summary from GJE of work functions in some metals. –Forwarded Message Attachment–

No Horst, lattice energy is the energy given off when oppositely charged ions in the gas phase come together to form a solid. The work function is the energy required to extract an electron from a solid – from the highest filled level in the Fermi distribution of a solid. Needless to say, the work function for Cs is also lower than for other metals, (Cs 1.82eV, Na 2.46eV, for example – see table below). Richardson’s equation gives an estimate of the work function:

I = AT 2 exp(−/kT) where I is the thermionic current, T the absolute temperature, k is Boltzmann’s constant and A is a constant having the theoretical value 120 amp cm−2 deg−2. AS you know, may also be estimated photoelectrically for metals. Einstein’s expression for the photoelectric effect is hv = e + E, where E is the kinetic energy of the ejected photoelectron. The photoelectric current J released when light of energy hv falls on the surface of a metal, for which the threshold frequency is given by hv0 = e (for then E = 0), is given by the Fowler equation

J = B(kT2).f{(hv − hv0)/kT} where f is a universal function of (hv − hv0)/kT and B is constant provided that hv is near to hv0. can also be estimated by the contact potential difference (c.p.d.) VAB that exists between the surfaces of two solids A and B of work functions A and B, when connected electrically, since

B − A = eVAB for the two solids at the same temperature. The method involves a prior knowledge of the work function of one of the solids if that of the other is to be measured absolutely. A fourth method involves the field emission of electrons when an external electric field F is applied. Typical errors of the tabulated quantities for the metals are 0.02 eV. Adsorbates or contaminants will usually reduce the measured and different crystal faces of the same material have differing values of . Work functions

Metal Work function φ/eV Metal Work function φ/eV

Photoelectric C.P.D.

Thermionic Photoelectric C.P.D.

Li . . . . . — 2.32

Nb . . . . . 4.30 — 4.37

Na . . . . . 2.36 2.46

Mo . . . . . 4.33 4.49 4.21

K . . . . . 2.30 2.01

Ta . . . . . 4.33 4.30 4.22

Rb . . . . . 2.05 —

W . . . . . 4.55 4.55 4.55

Cs . . . . . 1.95 1.82

Re . . . . . 4.72 — —

Be . . . . . — 3.91

Ti . . . . . 4.10 4.33 4.20

Mg . . . . . — 3.61

Cr . . . . . 4.60 4.44 —

Ca . . . . . 2.87 —

Mn . . . . . — 4.08 —

Ba . . . . . 2.52 2.35

Fe . . . . . — 4.60 4.16

Co . . . . . — 4.97 —

Zn . . . . . 3.63 4.11

Ni . . . . . 5.24 5.15 5.25

Cd . . . . . — 4.22

Zr . . . . . 4.00 — —

Al . . . . . 4.28 4.19

Hf . . . . . 3.65 — —

Ga . . . . . 4.35 —

In . . . . . 4.08 —

Ru . . . . . — 4.71 4.73

Rh . . . . . 4.72 — —

Sn . . . . . 4.28 4.43

Pd . . . . . — 5.40 —

Pb . . . . . 4.25 3.83

Ir . . . . . 4.57 — —

Pt . . . . . 5.36 5.63 —

Cu . . . . . 4.65 4.51

Ag . . . . . 4.26 4.29

Th . . . . . — — 3.71

Au . . . . . 5.10 5.28

U . . . . . 3.47 3.47 3.63

As . . . . . 4.79 —

C (dag) . . . . — — 4.65–5.0

Sb . . . . . 4.56 —

Si . . . . . — 4.95 4.75

Bi . . . . . 4.34 —

Ge . . . . . — 5.15 4.83

Best, Gareth

Gareth,

is the lattice energy you described identical with what is called “work function” by the solid state physicists? Thi is the energy required to pull out an electron from the crystal through the surface. It is amounts to some eV.

Horst

The next generation of MSN Hotmail has arrived – Windows Live Hotmail

Email straight to your blog, upload jokes, photos and more. Windows Live Spaces, it’s FREE! _________________________________________________________________ Try Live.com – your fast, personalised homepage with all the things you care about in one place. http://www.live.com/?mkt=en-gb

This line of research looks very promising – and the climate section will no doubt begin to attract a lot of interest as the search engines lock into it. I have just got in half a ton of anthracite here from Tower Colliery, the coal man (who is a fluent Welsh speaker like myself) did not even ask me to pay for it, he will just show up one day. I will even have to remind him that I owe him for the coal. This is an echo of the old mining community here, which was close knit and a true native Welsh speaking community due to the constant dangers, dust dangers and accidents. The new coal industry I envisage for Wales would be ultra modern with very strict safety standards and all the latest scrubbing techniques, producing a variety of products. I wonder when the Welsh Assembly is going to get around to the real world of heavy industry.