ON SOLITONIC DEFECTS IN HYDROGEN-BONDED (HF)(X)

Results of first-principles, density-functional calculations on single , periodic chains of (HF)(x) are reported. The chains consist of repea ted unit cells each containing four HF monomers and the structures are constructed such that they resemble periodically repeated solitonic ( ionic or Bjerrum) defects. Special emphasis is put on exploring how ex perimental studies of the electronic properties are influenced by the presence of the solitons, i.e., whether experiments can demonstrate th e presence of the solitons. It is found that studies of the electron d ensity (in position or momentum space) are less convenient in this res pect, whereas studies of the electronic single-particle energies may b e used. Certain experimental techniques may also be able to distinguis h between ionic and Bjerrum defects.