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Subsections


The MCDHF/MCHF Data Collection

Introduction

The main goal of the Website is to store and allow acces to the world to accurate atomic transition data for light atoms. The data have been computed and analyzed at Vanderbilt University under the direction of Prof. Charlotte F. Fischer. The computational schemes include correlation and relativistic effects, through Breit-Pauli interactions. The data are organized by sequences and by atoms, Figure  3.5, and are accessible through the main page at
 
http://www.vuse.vanderbilt.edu/~cff/mchf_collection/
, which displays the Periodic Table. In addition to Atomic data, the Web site contains source code, an interactive version of the hf program and information relevant to the computational methods utilized for mass production.

Figure 3.5: Main web page of the MCDHF/MCHF Collection. The website contains ab initio and energy adjusted transition data for the Li- through Ne-like electronic sequences (Z=4-24)
\begin{figure}\begin{center}
\centerline{\psfig{figure=tex/fig/mchf_image0.eps,width=12cm}}\end{center}\end{figure}

Atomic data

Goals

By conducting systematic large-scale relativistic studies of a portion of the spectra including the ground state, the MCDHF/MCHF Collection aims at creating accurate ab initio collection of atomic transition data of the light atoms A detailed agreement between ab initio methods for computing atomic spectroscopic data and experiment requires the relativistic effects to be included even in light atoms. In addition, fine structure levels, inter-combination lines, and lifetimes of some levels can be accurately determined only by considering the relativistic effects (spin-orbit, spin-spin, and spin-other-orbit) and all computed data have included them.

Methods

The wave functions for both initial and final states were determined using the nonrelativistic multiconfgiurational Hartree-Fock (MCHF) approach. The wave functions were built from a basis of one-electron spin-orbital functions and were expanded in terms of configuration state functions (CSF). In order to keep the calculations in reasonable bounds the method of Restrictive Active Space (RAS) was applied. The size of the active sets (characterized by the largest principal quantum number, n) was incremented until a convergence of both the LS transition energy and the two forms of LS line strength were achieved.

In the Breit-Pauli approximation, terms for a specific J value interact, and this requires that mixing effects between terms be considered. The traditional MCHF method was modified to permit a simultaneous optimization of the weighted energy expressions derived from multiple terms. This allowed a single orbital set to represent a choice of terms with strong relativistic mixing. Then, by diagonalization of the Breit-Pauli Hamiltonian a few selected eigenvalues were determined. The bi-orthonormal method was applied to compute the transition data.

Results

. The MCDHF/MCHF Collection contains extensive transition data currently for seven isoelectronic sequences (LI, Be, B, C, N, O, F, Ne). The method of simultaneous optimization considerably enhanced the means of computing a common radial basis when many terms exhibit relativistic mixing effects. The method allows for a simultaneous optimization of the weighted energy functional of a set of selected terms and eigenvalues. Applying the Breit-Pauli corrections included the relativistic effects. The accuracies of the transition energy, rates and lifetimes were compared with some high precision experiments and benchmark studies. The transition energies compared to the observed were accurate within a fraction of percent, and the accuracy of the transition rates was very often less than 1data were evaluated based on discrepancies between observed and theoretical energy, and the velocity and length forms of line strength.

Computational Methods

This page contains links to atsp2K, graspVU source code, installation help, this help manual converted to html format, and additional information about how to setup run parallel jobs on the Linux cluster and on seaborg. Additionally cluster management information can be found.

Hartree-Fock Program

A web interfaced interactive version of the Hartree-Fock program can be accessed by clicking on the link HF Program. Additionally, the user can read the theory behind the hf program. The Hartree-Fock program is a Java interfaced FORTRAN program which is installed on hf5.

Note to the system administrator of hf5: If problem occurs with the hf program on the Web, hf5 should be checked for the following:

Both, the Apache server and the hf Java server are configured to automatically start upon rebooting of the node hf5. While the scripts for the Apache server are default in the RedHat 7.1 installation and have not been modified, the hf Java server startup script is executed in /etc/rc.local (this script starts the local services). /etc/rc.local starts the hf Java server by executing the script /var/www/html/sh_start_HFapplet_server. Note that in order to start the hf Java server it is sufficient to execute as a root:

#cd /var/www/html/
#./_start_HFapplet_server

The file /var/www/html/log.hf_applet keeps information about all IP's which had accessed the hf program and performed runs (The output below shows a portion of this file and IP's from all over the world for the last 2 months > 1000 accesses):

(georgio@hf5)128% tail /var/www/html/log.hf_applet 
Server: Connection to 139.91.195.54/139.91.195.54 established
Server: Connection to elena.iesl.forth.gr/139.91.195.54 established
Server: Connection to 195.54.103.39/195.54.103.39 established
Server: Connection to kublai.djingis.m.se/195.54.103.39 established
Server: Connection to alain.m36sci.nrc.ca/132.246.22.169 established
Server: Connection to pcphy117.physik.uni-kl.de/131.246.11.210 established
Server: Connection to atm.nist.gov/129.6.84.160 established
Server: Connection to useraa87.uk.uudial.com/62.188.130.87 established
Server: Connection to natpool1-1.bsu.unibel.by/195.50.4.44 established
Server: Connection to d80h103.public.uconn.edu/137.99.80.103 established
Server: Connection to duchamp.phy.nist.gov/129.6.169.31 established
Server: Connection to capsule.neep.wisc.edu/128.104.185.245 established
Server: Connection to cfppp2-17.harvard.edu/131.142.14.117 established
Server: Connection to P-1.251.EUnet.yu/213.240.1.251 established
Server: Connection to mdm3428.chem.utah.edu/128.110.196.147 established
Server: Connection to wigner.physik.uni-kassel.de/141.51.196.23 established
Server: Connection to mdm3428.chem.utah.edu/128.110.196.147 established
Server: Connection to naglfar.sljus.lu.se/130.235.91.187 established
Server: Connection to mach.ulb.ac.be/164.15.128.3 established
Server: Connection to berry.phys.nd.edu/129.74.75.176 established
Server: Connection to hgberry.phys.nd.edu/129.74.76.3 established
Server: Connection to coral-56-96.pompano.net/24.26.56.96 established
Server: Connection to elettra.arcetri.astro.it/193.206.155.27 established
Server: Connection to 1Cust29.tnt9.tco2.da.uu.net/63.15.231.29 established
Server: Connection to coral-56-96.pompano.net/24.26.56.96 established
Server: Connection to hgberry.phys.nd.edu/129.74.76.3 established
Server: Connection to 129.74.76.24/129.74.76.24 established
Server: Connection to hal4.usm.uni-muenchen.de/129.187.204.12 established
Server: Connection to lavender.phys.put.poznan.pl/150.254.132.5 established
Server: Connection to ykkim.phy.nist.gov/129.6.169.2 established
Server: Connection to m133-48.bgsu.edu/129.1.133.48 established
Server: Connection to ljclap.physics.utoledo.edu/131.183.161.100 established
Server: Connection to meltemi.physics.uoc.gr/147.52.180.194 established
Server: Connection to bethe.fy.chalmers.se/129.16.113.136 established


next up previous contents
Next: NONH Up: ATSP2K manual Previous: Computing Atomic Transitions   Contents
2001-10-11