BERTHA

Checked by R. T. Arnold, Fred Smith, and Bertha Lewis. 

The author s work has included the development of the Sandia Bear and Bertha explosive recovery fixtures, that provide a standardized set of fixtures in which recovery experiments can be routinely carried out at peak shock pressures from 4 to 500 GPa. Shock-induced, mean-bulk temperatures from 50 to 1200°C are achieved with variation in the density of the powder compacts under study. 

Fig. 6.5. The shock-compression conditions imposed on powder compacts preserved for post-shock analysis are controlled by details of the shock-recovery fixtures. In all the work of Chap. 6, the Sandia Bear and Bertha fixtures are used. The fixtures represent a standardized system that is highly reproducible and has been subject to extensive numerical simulation.

The high explosives, baratol or Composition B-3, are used to produce the plane wave loading into the driver plates. These explosives have been widely studied in substantial work at Los Alamos. Plane waves are introduced into the explosive pads with either P-22 or P-40 plane-wave generators developed at Los Alamos. The Bear system is based on the 56 mm diameter of the P-22, while the larger sample size Bertha system is based on the 102 mmdiam of the P-40. More details on sample dimensions are reported by Graham [87G03]. 

Table 6.3. Sandia Bear and Bertha fixture characteristics.

Address Bertha-von Suttner, Strasse 7 34111 Kassel Geimany... 

Paris Guns. See under Big Bertha, Paris Gun and Other German Big Guns of WWI and WWII in VoJ 2, B113-R... 

ARIEL EWENSON, BERTHA CROITORU AND AVRAM BECKER ... 

T771 A. Sapi, F. Bertha, J. Fetter, M. Kajtar-Peredy, G.M. Keseru, K. Lempert, Tetrahedron 1996,... 

The authors thank Mr Fajar Zulkarnain Lubis, Mr Deddy Triono (Faculty of Pharmacy, Arlangga University, Surabaya), and Ms Bertha Oktarina (Bernofarm, Sidoarjo), for their kind technical assistance. 

Poochikian, G. and Bertha, C.M., Regulatory view on current issues pertaining to inhalation drug products, Respiratory Drug Delivery VIII Conference, Vol. 1, 2000, pp. 159-164 [www.rddonline.com]. 

Bowen WD, Vilner BJ, Williams W, Bertha CM, Kuehne ME, Jacobson AE. (1995). Ibogaine and its congeners are sigma 2 receptor-selective ligands with moderate affinity. Eur J Pharmacol. 1279(1) Rl-3. 

Layer RT, Skoinick P, Bertha CM, Bandarage UK, Kuehne ME, Popik P. (1996). Structuraiiy modified ibogaine anaiogs exhibit differing affinities for NMDA receptors. Eur J Pharmacol 309(2) 159-65. 

Table 6 Matrix Dirac-Hartree-Fock (Edhf) and Hartree-Fock (Ehf) energies calculated using BERTHA. The Gaussian exponential parameters are those of the non-relativistic sets derived by van Duijenveldt and tabulated in Poirier et al [36]. Thejirst-order molecular Breit energy, Eb, v as calculated using methods described in [12] relativistic corrections to Ehf collected in the column labelled E energies are in atomic units.

Table 8 Second-order many-body perturbation theory corrections to beryllium-like ions using non-relativistic (E ), Dirac-Coulomb (E ) and Dirac-Coulomb-Breit (E ) hamiltonians, obtained using the atomic precursor to BERTHA, known as SWIRLES. Basis sets are even-tempered S-spinors of dimension N= 17, with exponent sets, Xi generated by Xi = abi-i, with a = 0.413, and p = 1.376. Angular momenta in the range 0 < / < 6 have been included in the partial wave expansion of each second-order energy, and the total relativistic correction toE has been collected as Ef. All energies in hartree.

Table 7 Estimates of total relativistic correction, E, and the first-order Breit energy correction,, obtained by combining the atomic or ionic contributions indicated by the second column. They may be compared with the values of the total relativistic correction, Ek. and thefirst-order Breit interaction, Eb, obtained directly from matrix Dirac-Hartree-Fock and Hartree-Fock calculations of the molecular structure using BERTHA [12], Only the results of the Iis7p2d atom-centred basis sets for Ek and Eb are quoted. All energies in atomic units.

PROGRESS WITH BERTHA A RELATIVISTIC ATOMIC AND MOLECULAR STRUCTURE PACKAGE... 

Abstract. BERTHA is a 4-component relativistic molecular structure program based on relativistic Gaussian (G-spinor) basis sets which is intended to make affordable studies of atomic and molecular electronic structure, particularly of systems containing high-Z elements. This paper reviews some of the novel technical features embodied in the code, and assesses its current status, its potential and its prospects. 

This paper outlines the current status of the BERTHA program. This has been named (with her approval) after Lady Jefferies (f902-f999) nee Bertha Swirles), a colleague of D.R. Hartree at Cambridge University and a distinguished applied mathematician who, amongst other achievements, wrote the earliest paper on relativistic self-consistent fields for atoms [f]. 

A full account of the theory of relativistic molecular structure based on standard QED in the Furry picture will be found in a number of publications such as [7, Chapter 22], [8, Chapter 3]. These accounts use a relativistic second quantized formalism. For present purposes, it is sufficient to present the structure of BERTHA in terms of the unquantized effective Dirac-Coulomb-Breit (DCB) A-electron Hamiltonian ... 

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