4. CONCLUSION
The cold fusion phenomenon (CFP), which is
perplexing and puzzling from conventional points of view in nuclear physics and
solid-state physics, is explained as a phenomenon of solid state-nuclear
physics where new states of neutrons play essential roles to induce nuclear
reactions different from those in free space. It seems that the realization of
the neutron valence band is a form of self-organization in complex chaotic
systems, fcc transition-metal hydrides and deuterides.
CFP was explained, for the first time,
consistently by phenomenological models, the TNCF and the neutron drop models.
The neutron drop model assumes neutron drops AZ△ made of Z
protons and (A-Z) neutrons in the thin neutron gas, which is
formed in the cf-matter at boundary (surface) regions.
The working concept, the cf-matter, is defined
as "the field where the CFP occurs in CF materials." This is used to
explain complex events in the CFP. It became clear through the investigation in
this paper that the cf-matter is spread over CF materials in general. At
boundary and surface regions, the cf-matter contains high-density neutron drops
in a thin neutron gas while in the volume it contains only a few of them in
accordance with experimental data.
The neutron drop AZ△ interacts with a
nucleus AZ△X to accelerate the decay process of A’Z’X
if it is unstable or to giveνneutrons andν’ protons to A’Z’△X (ν, ν’ = 0, 1, 2, - - - -)
thus inducing nuclear transmutations (NT). Especially, an explanation of mass
spectra of nuclear products observed in CFP (e.g. Miley 1996) can be explained
as fission products of unstable nuclides A'+ν+ν’Z'+ν’X’ formed by
the above process as done by Fisher using a hypothetical polyneutrons (Fisher
1998).
A brief microscopic scenario for these phenomenological
models is given as follows. Formation of neutron valence bands in fcc
transition-metal hydrides and deuterides was shown using relevant knowledge in
nuclear physics and in solid-state physics. Excitation of occluded protons
(deuterons) from ground octahedral sites to excited tetrahedral sites with
spatially extended wave functions, on one hand, and excitation of neutrons in
lattice nuclei to excited states near zero with spatially extended wave
functions, on the other, make the state favorable for the neutron valence
bands.
Trigger reactions between trapped thermal neutrons in
neutron conduction and/or valence bands and exotic nuclei A’Z’X
liberate energy which is used for the excitation of occluded hydrogen isotopes
to higher energy levels and also for the excitation of neutrons in lattice
nuclei to levels near zero.
Then, the local coherence of neutron Bloch waves
at boundary (surface) regions of a sample enhances the density of neutrons at
these regions, making the density of the thin neutron gas higher there.
Formation of the cf-matter, neutron drops in the thin neutron gas, is realized
by the local coherence in neutron valence bands at boundary regions. It is
possible deuterides are favorable for the cf-matter formation than hydrides due
to the existence of a neutron in a deuteron unless other conditions differ so
much. In the process of the cf-matter formation, such concepts related with
neutrons in solids as neutron Moessbauer effect (Kozima 1994b) and the neutron
affinity (Kozima 1998a) may work positively.
The neutron drops AZ△ make specific reactions
in CF material possible: (a) Rare emission of gamma rays in CFP means
that main decay channels of excited states of a nucleus in CF materials are
through neutron drop-nuclear interactions rather than intranuclear conversions
such as in free space. (b) Various nuclear transmutations of nuclides
become possible in the \cfm through multi-nucleon transfer to nuclides: NTD,
NTF, NTA, are explained by absorption of ν neutrons by a nuclide AZX
(ν > 1); ν = 1 for NTD
accompanied by decays, ν >> 1
for NTF accompanied by fissions, and \nyuu andν’ > 1 for NTA
withν’ a number of
protons absorbed simultaneously with neutrons. Frequent observation of Fe in
CFP might be explained by transitions of neutron drops AZ△ into stable nuclides AZ△X in the cf-matter.
Only one characteristic of the neutron wave
function in excited states and one of the proton (deuteron) wave function in fcc
transition-metal hydrides (deuterides) were taken up in Chapter 3 to show possible
formation of the neutron valence band even though other characteristics pointed
out in Chapter 2 should be relevant to CFP.
Several crucial factors not properly treated yet
are as follows: (1) the first is spin-dependence of nuclear interactions, (2) the
second is the effect of the imaginary part of the neutron-nucleus interaction
resulting in absorption of neutrons by lattice nuclei not considered in our
treatment, (3) neglect of hybridization of wave functions ψn{n, x;
ai) with different n's in band formation, and (4) the
fourth is the difference in the proton-neutron and the deuteron-neutron
interactions on the super-nuclear interaction. (5) The fifth is correct
wave functions of occluded protons and deuterons at their excited band states.
(6) The sixth is the thermal motion of lattice nuclei which will make
the band structure blur unless the super-nuclear interaction is strong enough
to overcome the effect of the thermal motion. (7) The seventh is the
surface states of neutrons at boundaries different from the Bloch states taken
up in this paper. (8) The eighth is roles of electrolytes in formation
of surface layers with extraneous composition from matrices of cathodes in
electrolytic systems. These factors should be properly considered to make the
estimation given in this paper more quantitative.
The spin-dependence of the nuclear interaction between
neutron and proton (deuteron) will be detected as reinforcement of CFP when
spins of occluded protons (deuterons) are polarized by the proton-spin
(deuteron-spin) polarization technique.
We can add several words on application of CFP.
Realization of necessary and sufficient conditions for creation of the
cf-matter in solids is subtle problem depending on many factors such as
neutrons in excited states of lattice nuclei and protons (deuterons) in excited
states in solids, as shown in this paper theoretically. On the other hand,
realization of CFP is with the qualitative reproducibility and sporadicity,
experimentally. If we know how to realize the optimum condition in samples,
however, it will be possible to use CFP for such applications as energy
generation, nuclear transmutation, acceleration of nuclear decay process and so
forth with high efficiencies. Elucidation of physical mechanisms of CFP will
help to attain this goal.
The author would like to express his heart-felt
thanks to the following people who helped him during his arduous CF research
efforts. John Dash of Portland State University, USA made his stay at PSU from
September 2000 possible. Dash read a large part of the manuscript of this paper
and also improved the English. Mitsuji Kawai of Kyushu University, Japan and
Makoto Takeo of PSU made many valuable comments. Many collaborators have worked
with him during these more than ten years. Many researchers including the late
Makoto Okamoto of Tokyo Institute of Technology and Tohoku University, Japan
supported him by supplying their data frankly and discussing physics together
earnestly.
This work is supported by a grant from the New
York Community Trust and by the Professional Development Fund for part-time
faculty of Portland State University.