Leif Holmlid
Professor emeritus

Atmospheric Science
Department of Chemistry
University of Gothenburg

Phone: +46(0)31-7869076
Email: holmlid@

My main research interest since some time is dense and ultra-dense hydrogen forms. These materials are the lowest energy states of Rydberg Matter. This is a state of matter of the same status as liquid or solid, since it can be formed by a large number of atoms and small molecules. For a more complete description, see Wikipedia.

The lowest state of Rydberg Matter in excitation state n = 1 can only be formed from hydrogen (protium and deuterium) atoms and is designated H(1) or D(1). This is dense or metallic hydrogen, which we have studied for a few years. The bond distance is 153 pm, or 2.9 times the Bohr radius. It has a density of approximately 0.6 kg / dm3. See for example Ref. 167 below!

A much denser state exists for deuterium, named D(-1) or d(-1). We call it ultra-dense deuterium. This is the inverse of D(1), and the bond distance is very small, equal to 2.3 pm. Its density is extremely large, >130 kg / cm3. Due to the short bond distance, D-D fusion is expected to take place easily in this material. See Wikipedia! See also a press release and listen to a radio interview in Swedish (10.50 min into the program). A similar but not identical material formed from protium is called p(-1) or ultra-dense protium.

A theoretical description of ultra-dense deuterium D(-1) has been published by Friedwardt Winterberg. See these links to Journal of Fusion Energy, and Physics Letters A. The first experiments showing nuclear fusion in D(-1) can be found as Refs. 191 and 201 below.

Ultra-dense deuterium was recently shown to be the first room-temperature superfluid, see Ref. 196 below. It also shows a Meissner effect at room temperature (Ref. 204) and is thus probably also superconductive at room temperature.


Laser experiment on ultra-dense deuterium

The initial laser process in ultra-dense deuterium

Some recent publications:

210. P.U. Andersson and L. Holmlid, "Fast atoms and negative chain cluster fragments from laser-induced Coulomb explosions in a super-fluid film of ultra-dense deuterium D(-1)". Phys. Scripta, accepted.

209. L. Holmlid, "Method and apparatus for generating energy through inertial confinement fusion".

208. F. Olofson and L. Holmlid, "Superfluid ultra-dense deuterium D(-1) on polymer surfaces: structure and density changes at a polymer-metal boundary".
J. Appl. Phys. 111, 123502 (2012);DOI: 10.1063/1.4729078

207. F. Olofson, A. Ehn, J. Bood, L. Holmlid, "Large intensities of MeV particles and strong charge ejections from laser-induced fusion in ultra-dense deuterium".
39th EPS Conference & 16th Int. Congress on Plasma Physics, Stockholm, 2012; 12-02-20, P1.105.

206. F. Olofson and L. Holmlid, "Detection of MeV particles from ultra-dense protium p(-1): laser-initiated self-compression from p(1)".
Nucl. Intr. Meth. B 278 (2012) 34-41. DOI: 10.1016/j.nimb.2012.01.036.

205 L. Holmlid, "MeV particles from laser-initiated processes in ultra-dense deuterium D(-1)".
Eup. Phys. J. A 48 (2012) 11. DOI: 10.1140/epja/i2012-12011-0.

204. P.U. Andersson, L. Holmlid, and S.R. Fuelling, "Search for superconductivity in ultra-dense deuterium D(-1) at room temperature: depletion of D(-1) at field strength > 0.05 T".
J. Supercond. Novel Magn. 25 (2012) 873-882. DOI: 10.1007/s10948-011-1371-6.

203. P.U. Andersson and L. Holmlid, "Cluster ions DN+ ejected from dense and ultra-dense deuterium by Coulomb explosions: fragment rotation and D+ backscattering from ultra-dense clusters in the surface phase".
Int. J. Mass Spectrom. 310 (2012) 32-43. DOI: 10.1016/j.ijms.2011.11.004

202. L. Holmlid, "Experimental studies of clusters of Rydberg matter and its extreme dense forms". Invited review.
J. Cluster Sci. 23 (2012) 5-34. DOI: 10.1007/s10876-011-0417-z.

201. P.U. Andersson and L. Holmlid, "Fusion generated fast particles by laser impact on ultra-dense deuterium: rapid variation with laser intensity".
J. Fusion Energy 31 (2012) 249-256. DOI 10.1007/s10894-011-9468-2.

200. L. Holmlid, "Sub-nanometer distances and cluster shapes in dense hydrogen and in higher levels of hydrogen Rydberg Matter by phase-delay spectroscopy".
J. Nanopart. Res. 13 (2011) 5535-5546. DOI 10.1007/s11051-011-0543-4..

199. L. Holmlid, "Diffuse interstellar bands (DIB) in space: almost all bands calculated from co-planar doubly excited He and metal atoms embedded in Rydberg Matter".
Astrophys. Space Sci. 336 (2011) 391-412. DOI 10.1007/s10509-011-0795-6.

198. L. Holmlid, "Deuterium clusters DN and mixed K-D and D-H clusters of Rydberg Matter: high temperatures and strong coupling to ultra-dense deuterium".
J. Cluster Sci. 23 (2012) 95-114. DOI 10.1007/s10876-011-0387-1.

197. L. Holmlid, "High-charge Coulomb explosions of clusters in ultra-dense deuterium D(-1)".
Int. J. Mass Spectrom. 304 (2011) 51–56. doi: 10.1016/j.ijms.2011.04.001.

196. P.U. Andersson and L. Holmlid, "Superfluid ultra-dense deuterium D(-1) at room temperature".
Phys. Lett. A 375 (2011) 1344–1347. doi:10.1016/j.physleta.2011.01.035.

195. L. Holmlid, "Large ion clusters HN+ of Rydberg Matter: stacks of planar clusters H7".
Int. J. Mass Spectrom. 300 (2011) 50-58. doi:10.1016/j.ijms.2010.12.008.

194. P. U. Andersson, B. Lönn and L. Holmlid, "Efficient source for the production of ultra-dense deuterium D(-1) for laser-induced fusion (ICF)". Rev. Sci. Instrum. 82 (2011) 013503. doi:10.1063/1.3514985.

193. M. Trebala, W. Rozek, L. Holmlid, M. Molenda, and A. Kotarba,"Potassium stabilization in ß-K2Fe22O34 by Cr and Ce doping studied by field reversal method". Solid State Ionics (2011) . doi:10.1016/j.ssi.2010.08.004.

192. L. Holmlid, "Common forms of alkali metals - new Rydberg Matter clusters of potassium and hydrogen". J. Clust. Sci 21 (2010) 637-653. DOI: 10.1007/s10876-010-0291-0.

191. S. Badiei, P. U. Andersson and L. Holmlid, "Laser-driven nuclear fusion D+D in ultra-dense deuterium: MeV particles formed without ignition". Laser Part. Beams 28 (2010) 313-317 doi:10.1017/S0263034610000236.

190. P. U. Andersson and L. Holmlid, "Deuteron energy of 15 MK in a surface phase of ultra-dense deuterium without plasma formation: temperature of the interior of the Sun". Phys. Lett. A 374 (2010) 2856–2860
DOI: 10.1016/j.physleta.2010.03.009

189. S. Badiei, P. U. Andersson and L. Holmlid, "Production of ultra-dense deuterium, a compact future fusion fuel". Appl. Phys. Lett. 96 (2010) 124103. doi:10.1063/1.3371718.

188. F. Olofson, P. U. Andersson and L. Holmlid, "Rydberg Matter clusters of alkali metal atoms: the link between meteoritic matter, polar mesosphere summer echoes (PMSE), sporadic sodium layers, polar mesospheric clouds (PMCs, NLCs), and ion chemistry in the mesosphere". arXiv.org 10-02-08, astro-ph/1002.1570. http://arxiv.org/abs/1002.1570

187. S. Badiei, P.U. Andersson and L. Holmlid, "Laser-induced variable pulse-power TOF-MS and neutral time-of-flight studies of ultra-dense deuterium". Phys. Scripta 81 (2010) 045601. doi: 10.1088/0031-8949/81/04/045601.

186. P. U. Andersson and L. Holmlid, "Ultra-dense deuterium: a possible nuclear fuel for inertial confinement fusion (ICF)". Phys. Letters A 373 (2009) 3067–3070. doi:10.1016/j.physleta.2009.06.046.

185. L. Holmlid, H. Hora, G. Miley and X. Yang, "Ultrahigh-density deuterium of Rydberg matter clusters for inertial confinement fusion targets". Laser and Particle Beams 27 (2009) 529–532.

184. A. Kotarba and L. Holmlid, "Energy-pooling transitions to doubly excited K atoms at a promoted
iron-oxide catalyst surface: more than 30 eV available for reaction". Phys. Chem. Chem. Phys. 11 (2009) 4351-4359. DOI: 10.1039/b817380j.

183. S. Badiei, P. U. Andersson and L. Holmlid, "High-energy Coulomb explosions in ultra-dense deuterium: time-of-flight mass spectrometry with variable energy and flight length". Int. J. Mass Spectrom. 282 (2009) 70-76. Link to abstract and paper.

182. L. Holmlid, "Nm interatomic distances in Rydberg Matter clusters confirmed by phase-delay spectroscopy". J. Nanopart. Res. 12 (2010) 273-284. DOI 10.1007/s11051-009-9605-2.

181. L. Holmlid, "Light in condensed matter in the upper atmosphere as the origin of homochirality: circularly polarized light from Rydberg Matter". Astrobiol. 9 (2009) 535-542.

180. L. Holmlid, "Nuclear spin transitions in the kHz range in Rydberg Matter clusters give precise values of the internal magnetic field from orbiting Rydberg electrons". Chem. Phys. 358 (2009) 61–67.

179. S. Badiei, P. U. Andersson and L. Holmlid, "Fusion reactions in high-density hydrogen: a fast route to small-scale fusion?" Int. J. Hydr. Energy 34 (2009) 487-495. Link to abstract and paper.

Popular science:

L. Holmlid, "Rydberg Matter - diary from the laboratory" (translation of title in Swedish "Rydbergsmateria - dagbok från labbet". Forskning och Framsteg 38:4 (2003) 14-17.