(LMTO) calculations within the local spin density approximation (LSDA), as implemented in the STUTTGART TB-LMTO-ASA program [14]. We have also performed.

• Tb-lmto-asa

LMTO-ASA and basic package (v7.0) LMTO-ASA and basic package (v7.0) This file documents the basic LMTO and TBE program packages. Written by M.

Van Schilfgaarde, A.T.Paxton, J. Klepeis and M. Methfessel email Mark.vanSchilfgaarde@asu.edu Documentation for Version 7.0, July 2009 This documentation is oriented mainly for basic package ASA.

1. D-70569 Stuttgart. Self-consistent TB-LMTO-ASA potentials and wave. The program lm.run has to be run with the option.
2. “2013年理论与高性能计算化学国际会议” 7th Molecular Quantum Mechanics Conference Lugano (Switzerland), June 2-7, 2013; gaussian里的PCM低估反应.

Vsn.tar.gz, the electronic structure program implementing the (LDA) in a basis of linear muffin tin orbitals (LMTOs). (This text documents vsn=7.0.) The program described in this document makes an additional shape approximation to the LDA potential, known as the 'Atomic Spheres Approximation' (ASA). The ASA restricts space to overlapping spheres (with a geometry violation), and the potential is assumed to be spherically symmetric inside the spheres. Much of the description and input is relevant for the other packages as well, in particular the full-potential package (FP. Vsn.tar.gz), documented. Relatively minor additional input are needed for any of the other packages. `LMTO' is an acronym for 'Linear Muffin-Tin Orbitals,' which is a basis set for ab initio electronic structure calculations, usually within the context of the.

It was originally formulated (together with the LAPW method - Linear Augmented Plane Wave method) by O. For a long time, LMTO was implemented in the Atomic Spheres Approximation (ASA), an additional approximation that replaces the proper charge density and potentials by their spherical averages. At present the basic package consists of an ASA program with supporting programs as described below, and is implemented for what Andersen calls `second-generation' LMTO - namely a reworking of the original method into a tight-binding form, so that the orbitals are short-ranged. Since then Andersen has devised a `third-generation' LMTO, and more recently a `NMTO' scheme See O. Saha-Dasgupta, R. Jepsen, in Electronic Structure and Physical Properties of Solids: The Uses of the LMTO Method, edited by H.

Dreysse (Springer-Verlag, Berlin, 2000) which while formally make significant improvements over the `second-generation' LMTO, there remain difficulties with implementation. At present, this package has non-self-consistent NMTO scheme implementation, but it should largely be regarded as experimental, as there are practical pitfalls associated that haven't been fully worked out. There is also a full-potential implementation. It is more accurate than the ASA, but it also significantly slower. It uses an LMTO basis where the envelope functions are not screened but generalized to smoothed Hankel functions See M. Methfessel, M.

Van Schilfgaarde, and R. Casali, ``A full-potential LMTO method based on smooth Hankel functions,' in Electronic Structure and Physical Properties of Solids: The Uses of the LMTO Method, Lecture Notes in Physics, 535. (Springer-Verlag, Berlin) 2000; there is a postscript file included in this directory. The full-potential extension requires a supplemental package, distributed as FP. Vsn.tar.gz, and documented in. The basic package contain a variety of auxillary programs, described.

Extension packages, e.g. Vsn.tar.gz, and TBE. Vsn.tar.gz, contain a variety of electronic structure programs, including an empirical tight-binding program whose hamiltonian is taken from a user-chosen model. See for brief descriptions and hyperlinks.

This file is the main documentation of the ASA package, and most of the auxillary programs. See file for installation notes, the for help in getting started, the for a tutorial using the full-potential program. Augmented-wave programs, including the present suite, divide into an ``atomic' part and a ``band' part. In general the ``band' part requires potential parameters and structure constants as its input, from which it generates bands, energy moments, densities-of-states, etc.

The ``atomic' part takes moments as its input and produces potential parameters from it. The atomic part requires very little information beyond the moments and boundary conditions to completely specify the electronic structure within an atomic sphere, and the atomic program here embodies that idea. An LMTO-ASA calculation is self-consistent when the atomic part produces, from moments generated by the solid part, once again the same potential parameters that the solid part used to generate the moments in the first place. The self-consistency works by alternating between the solid part and atomic part, generating moments, then potential parameters, then moments again until the process converges. The program can be started either with the solid part, specifying potential parameters, or with the atomic part, specifying the moments. Because the method is a linear one, and because the density is (assumed to be) spherical, only three functions can carry charge inside a sphere per l channel (φ l 2, φ l ×(dφ l / dE), ( dφ l / dE) 2) and therefore the properties of a sphere, for a spherical potential and a linear method are completely determined by the first three energy moments Q 0, Q 1, and Q 2 of the density of states for each l channel, which are called the atomic number and the boundary conditions at the surface of the sphere. In some sense these numbers are ``fundamental' to a sphere; the atomic program will generate a self-consistent potential for a specified set of moments Q 0.Q 2 and boundary conditions.

This simplification depends on assumption of spherical densities, and is unique to the ASA. These codes (both ASA and full-potential codes) use 'logarithmic derivative parameters' P l to fix boundary conditions at the sphere surface; they are described.

Note: P l should not be confused with the 'potential functions' O.K. Andersen defines in his ASA theory.

Once a potential is specified, 'potential parameters' can be generated. 'Potential parameters' are a compact representation of information needed in a linear method to specify the hamiltonian. A description of how the parameters are generated and their significance is too involved to be described here; moreover, what parameters are generated depends on the choice of basis. (The 2nd generation potential parameters are particularly helpful because they refer to conceptually accessible quantities, such as the band-center parameter C, and the bandwidth parameter delta.) Particularly useful for the 2nd generation LMTO are Andersen's notes in the following references: O.K. Andersen, A.V.

Postnikov, and S. Savrasov, in 'Applications of Multiple Scattering Theory to Materials Science,' eds. Dederichs, A.

Gonis, and R.L. Weaver, MRS Symposia Proceedings No. 253 (Materials Research Society, Pittsburgh, 1992) pp 37-70. Jepsen and M.

Sob, in Lecture Notes in Physics: Electronic Band Structure and Its Applications, eds. Yussouff (Springer-Verlag, Berlin, 1987). And later descriptions, evolving beyond 2nd generation LMTO: O.K. Jepsen, and G. Krier in Lectures on Methods of Electronic Structure Calculations, edited by V. Andersen, and A. Mookerjee (World Scientific Publishing Co., Singapore, 1994), pp.

Arcangeli, R.W. Saha-Dasgupta, G. Jepsen, and I. Dasgupta in Tight-Binding Approach to Computational Materials Science, Eds. 491 (Materials Research Society, Pittsburgh, 1998) pp 3-34. From the point of view of the bands, the ASA Hamiltonian is completely specified by the potential parameters.

These are fundamental to the band program; it will generate moments Q 0.Q 2 from the eigenvectors of the Hamiltonian. (Alternatively, they may be generated via a Green's function, using programs lmgf or lmpg). Full self-consistency is achieved when the ``input moments' coincide with the ``output moments', or equivalently when the input potential parameters coincide with the output potential parameters. It is merely a matter of preference to whether to consider the moments as fundamental or the potential parameters. Unless performing some special-purpose function such as generating, lm works by iterating to, ASA style.

By virtue of the moments properties just described in the ASA, the self consistency procedure is a little different from the standard one. Lm can start equally as well from either potential parameters or moments, though it is generally customary to start from the moments, mainly because one can usually begin with a very simple starting guess (choosing the zeroth moment to be the charge of the free atom, the first and second to be zero) that is usually good enough to iterate to self-consistency. Actually, you don't need to specify a guess at all. Programs lm, lmgf, and lmpg will assume defaults values if none are supplied. If you have potential parameters at your disposal, you may choose to begin directly with a band calculation and need not worry about the moments. You will need to put the potential parameters in the proper atom file, described below. If you wish to make a self-consistent calculation, you must also supply the boundary condition for l channel.

In these programs, the boundary conditions is encapsulated in the 'continuously variable' principal quantum P described in the following paragraphs. To make a sphere self-consistent one needs the moments and also to specify the boundary condition on the wave function at the sphere radius, or what is essentially equivalent, the E ν of the wave function phi.

Tb-lmto-asa

For a given potential, there is a unique correspondence between the logarithmic derivative D ν at the sphere radius and E ν, so in principle, it is possible to specify either one. As a practical matter, however, it is only straightforward to make the sphere self- consistent by specifying the logarithmic derivative (since the potential changes while the sphere is made self-consistent). In an augmented wave method, there is the boundary condition on the wave function φ at the augmentation sphere radius.

More precisely, φ is called a partial wave since it is only a partial solution to the full Schrodinger equation. Partial waves must be matched to the envelope function at the augmentation sphere radius; the condition that all partial waves match smoothly and differentiably at all surfaces is the quantization condition that determines allowed eigenvalues. In the augmentation sphere we work in spherical coordinates.

For the purposes of constructing φ, (both in the ASA and FP methods) a spherical potential is assumed which means that the angular solutions are spherical harmonics and the radial solutions are partial waves φ l, with l the usual angular momentum number. In a linear method, φ l is assumed to vary smoothly with energy, and we take a Taylor series around some linearization energy E l, so that φ l( E) ≈ φ l( E l) + ( dφ l / dE) E l × φ l( E)-φ l( E l) It is this linearization of φ that simplifies the complicated matching conditions in augmentated wave methods, rendering the (nonlinear) matching conditions to into a linear algebraic eigenvalue problem. Any linear method must specify a linearization energy E l. Alternatively equivalent information is contained in the logarithmic derivative D l. For a given potential, there is a unique correspondence between the logarithmic derivative D l of φ, D l= dlnφ l/ dln E at the sphere radius and E l, so in principle, it is possible to specify either one.

D l is a cotangent-like function, varying between +∞ and -∞: it decreases monotonically with energy varying between (+&infin,-∞) over a finite window of energy. There is thus a multiplicity of energies for a given D l, one branch for each principal quantum number. For that reason we define a smooth quantity P l, which may be thought of as a smooth version of D l, and which also contains information about both the principal quantum number and the logarithmic derivative. P l is defined as P l = 0.5 - arctan( D l)/π + (princ.quant.number) Its integer part is the principal quantum number; its fractional part varies smoothly from 0 (for the bottom extreme of the band for that principal quantum number) to 1 (the top extreme of the band), and can be thought of in some sense as a 'continuously variable' principal quantum number. Note: P l should not be confused with the 'potential function' O.K.

Msvcr71.dll windows xp download. Andersen defines in his ASA theory. The above description of P l applies to both ASA and FP codes.

In the free atom code lmfa, P l and Q l, where Q l is the charge in orbital l, completely determine the density and potential of the free atom. (As noted, another boundary condition can be used in place of P l, but as a practical matter, however, it is only straightforward to make the sphere self- consistent by specifying the logarithmic derivative (since the potential changes while the sphere is made self-consistent). In the ASA codes ( lm, lmgf, lmpg), P l together with the moments Q, completely determine the potential in the crystal. Both must be supplied for lm to work. P l and Q are both input directly through the control file. (As mentioned, the programs will supply default values for both P l and Q, which for the most part are sufficient to get the program to converge to self-consistency.) Once you can make a band pass, the fractional part of P l will be automatically updated by the output of the band calculation (provided IDMOD is not 1; see description of IDMOD in the documentation on the control file), but P l must be supplied (in addition to the moments Q) if you choose to begin with moments. A word on choices for the fractional part of P l:.3 is quite free- electron-like and suitable for free-electron like l channels such as Si d electrons, while.8 is quite tight-binding like and suitable for deep states like Cu d orbitals.

To be safe, and probably avoid ghost bands, choose.5 for all l channels. In awkward cases, it is best to set the ADNF switch (see below) in the first few iterations; especially for heavier elements like Hf or f-electron elements like Gd. NOTE: In the case of spin-polarized calculations, the moments should all be half of what they are in non-spin polarized calculations. When iterating to self-consistency, you have a choice, through the parameter IDMOD described in the section, regarding the related pair of parameters P l and E l.

You may let P l and E l float to the center of gravity of the occupied part of the band (most accurate for self-consistent calculations); this is the default. You may also freeze alternatively P l or E l in the self-consistency cycle. This is more stable, and is preferable if there is difficulty in achieving convergence or if problems with ghost bands arise. The program iterates towards self-consistency by mixing the moments and the parameters P l as come out of the next iteration. A choice of Broyden, Anderson, or linear mixing is available; as explained in the description of category ITER in the file. There are a number of executable programs in the basic package, all of which are created from the same source file lmv7.f, using preprocessor ccomp described.

The most useful ones are: lm the self-consistent band program for the ASA lmstr generates the real-space structure constants for the ASA It must be invoked prior to invoking `lm'. Lmchk displays sphere overlaps.

There is an option to move atoms (empty spheres) to minimize the overlap. Lmctl writes out moments (to the log file) in the style of the input file, so that a complete calculation can be retained within a single file. See for an example.

Lmdos generates the electron density-of-states (DOS) and related quantities as a function of energy for plotting or other analysis. It can generate the total DOS (or DOS-related quantities), or resolve the total into partial contributions DOS-related quantities lmdos is equipped to deal with are:.integral d^k delta(E(k)-E), i.e. Just the DOS itself.integral d^k delta(E(k)-E) grad1 E(k). Grad2 E(k) from which a `diffusive' conductivity sigma12 can easily be computed within a relaxation time approximation.integral d^k delta(E(k)-E) grad1 E(k). Direction-vector which is the Landauer `ballistic' conductance along some unit direction-vector.core-level spectroscopy such as EELS derived from the full-potential program catdos concatenates density-of-states generated from different files into a single file. Lmscell generates supercells from smaller unit cells. Lmxbs generates an input file for Methfessel's ball-and-stick program xbs, which creates a 3D visual display of molecules.

You can create an input to his program to view the crystal structure specified in the ctrl file. Lmplan is a special-purpose program oriented to analysis of layer calculations. Lmimp imports potential data from other inputs to create trial potentials or densities. It can also import data from older versions, and Stuttgart versions, of the ASA package.

The following programs to generate electronic structure from empirical tight-binding hamiltonians, whose form the user specifies. They are included in the basic package.

There is some documentation. Tbe empirical tight-binding energy, forces, and dynamics With extension packages, there are also the following programs or extensions: lmf (FP) the self-consistent full-potential band program lmfa (FP) computes the free-atom densities and related information. Lmfa must be invoked prior to invoking lmf. Lm may be extended in the following ways. (NC) enables noncollinear extensions to the usual LSDA (OPTICS) calculates epsilon(omega) from LDA bands (SX) an ASA screened exchange, originally designed to correct bandgaps in semiconductors in an ab initio way. This latter is not well documented. Lmgf (GF) an ASA Green's function program.

This program uses Green's functions to perform an function approximately similar to program lm. Also a branch to compute magnetic exchange interactions. Lmpg (PGF) an ASA layer Green's function program. It is similar to lmgf, but uses a layer technique (real-space GF in one dimension, k-space in the other two) lmfgwd (GW) a driver for T. Kotani's all-electron GW implementation.

Additionally there are the following executables: rdcmd a program with a function approximately similar to a shell script that reads commands and executes them. It is used extensively in the test suites. Ccomp a program written in C which provides a fortran-compatible functionality approximately similar to that of the unix preprocessor, cpp.

It is documented in this file; see section `program ccomp' Plotting bands and DOS There is a plotting package available, FPLOT. Vsn.tar.gz, with a collection of programs suitable for plotting density-of-states ( pldos), bands ( plbnds) and other x-y plots. In includes a general-purpose plotting program, fplot, which creates x-y and contour plots, in postscript format. (As of this writing, the most recent package is FPLOT.3.39.tar.gz.) Run lm or some other band program to along symmetry lines you choose. Program plbnds reads this file and can either (1) generate a postscript file directly, or (2) generate input and a script to be read by the fplot program. In this way you can tailor a figure to taste.

For plotting partial DOS, see the -pdos option when using either lm or lmf. The control file, called ctrl. Extension is the main input file for all programs.

It together with command line arguments (see section 'Command-line switches') that affect some program execution flow, are the two principal (often sole) input streams needed to run these packages. The string extension is supplied as a command-line argument. If no extension is supplied on the command-line, `dat' is used as the extension.

Caution: The programs cannot read a ctrl file containing unreadable characters. Thus the invocation of any `lm' program has a form program-name -switches file-extension Nearly all files associated with the input file have the same extension appended to them as does the ctrl file. Thus if the ctrl file is called `ctrl.cr3si6', the is called `log.cr3si6'. Documents command-line switches. Other input files are: symmetry-line file: input for plotting energy bands along selected symmetry lines or for generating constant-energy contours such as a Fermi surface. This file (whose name is specified as a modifier with the command-line argument -band, described in the 'Command-line switches' section) can take on of several forms. First format: generate bands along specific symmetry lines.

The following sample input illustrates input for lines X-Gamma and Gamma-M for the simple cubic lattice. 21.5 0 0 0 0 0 X to Gamma 21 0 0 0.5.5 0 Gamma to M 0 0 0 0 0 0 0 The first number designates how many points along each line. The next six label the starting and ending q-points, respectively. Note that the last line must contain zeros.

Second format: generate bands for a 2D mesh in a specified plane for Fermi-surface plotting. This example applies to the bcc structure: vx range n vy range n height band 1 0 0 -1 1 51 0 1 0 -1 1 51 0.00 4,5 It saves bands 4,5 on a 51 x 51 mesh in the xy plane that passes through the origin. Site file: Normally site data is read through the ctrl file. However you may choose to read structural and site data through a separate file. It is intended that this file accommodate any of several formats. To date there is a format `standard' to this program, and one specified by Kotani. See for syntax of file structure.

You specify this option, and the file name using the `FILE=' token in the ctrl file, described in. Supercell generator `lmscell' has the capability to write a site file suitable for reading by other programs. Positions file: similar to the site file, but limited to specification of site positions. File is read (and named) by command-line switch -rpos=`filename'; and some programs (eg lmctl) will create this file when command-line switch -wpos=`filename' is supplied. Qpts file: Programs needing to loop over the Brillouin zone normally generate their own table of q-points. However, you may specify your own set of points (with certain restrictions; see description of token GETQP= in '). Here is a sample q-points file: 8 4 4 4 0 1 0.00 0.00 0.00 0.03125 2 -0.25 0.25 0.25 0.25000 3 -0.50 0.50 0.50 0.12500 4 0.00 0.00 0.50 0.18750 5 -0.25 0.25 0.75 0.75000 6 -0.50 0.50 1.00 0.37500 7 0.00 0.00 1.00 0.09375 8 0.00 0.50 1.00 0.18750 The first line specifies the total number of qp; the next three numbers are not used; the last should be zero.

Next follows lines, one line per qpt, each line with 5 numbers. The first merely labels the qp index; the next three are the qp in Cartesian coordinates. The last is the qp weighting factor, and the weights should sum to 2. The executables above generate many kinds of derivative files, briefly described below.

The file extension is suppressed in the following table. File (creator), and description - - ctrl the main input for all programs. It is never altered by any program in the package. Log (.) records a log of the most important output in abbreviated form.

Str (lmstr;binary) real-space structure constant file sdot (lmstr;binary) file containing energy derivative of str. Moms (lm,lmf;binary) partial weights of overlap matrix decomposed into Rl or Rlm channels. Used in two contexts: (1) to save information needed to the energy moments after the sampling weights are known, and (2) this is the data needed resolve density-of-states information into into Rl (or Rlm) channels.

For large systems, this file can become large, particularly if the dos need to be m-resolved. See also the command-line option. See file for the generation of the dos weights and their storage; program reads this or a similar file to create a the partial DOS. Qpp (lm;binary) information similar to moms, but intended for retaining information for nonspherical density inside MT spheres.

Wkp (lm,lmf;binary) table of band weights needed to find Fermi level, and corresponding fermi level. Mixm (lm,lmgf,lmpg,lmf;binary) retains prior iterations of sets of input and output moments.

Used by the Anderson or Broyden mixing scheme to accelerate convergence towards self-consistency. Usually you should delete these when starting a new calculation (such as changing the lattice constant) so it doesn't get used in subsequent runs. NB mixm is the default name of the mixing file, but this name may be set by the user. Tmp (.,binary) used for virtual memory or temporary storage atom-files (ASA) one file is assigned for each inequivalent atom in a calculation.

Its name is fixed by the species label ATOM= in the SPEC category of the control file, as described in. A complete file contains some general information, the moments, potential parameters, or other parameters such as matrix elements for needed for spin-orbit coupling or matrix elements of the gradient operator needed for optics calculations, and the ASA potential within the sphere, or some subset of this information. The moments and potential parameters are most read from this file if they are available; but it is possible to input the moments instead from the control file or the restart file as well. Data in the atomic file is grouped into categories delineated by a nonblank character in the first column. Examples of categories are: GEN: a table of miscellaneous data, such as the site atomic number MOMNTS: the 'log derivatives' P l and moments Q PPAR: the potential parameters. POT: the potential bnds (lm,lmf,lmbnd,tbbnd) energy bands, in a tabular form. See description of plotting package FPLOT.gz for plotting bands.

Dos (lmdos,tbdos) density-of-states, in tabular form. See description of plotting package FPLOT.gz for plotting dos. Sv (lm,lmgf,lmpg) records the total energy deviation from self-consistency for each iteration. Save (lm,lmgf,lmpg,lmf) outputs the magnetization and total energy each iteration in the self-consistency cycle, together with some variables assigned by the user. Used in conjunction with script startup/vextract, the total energy as a function of some user-specified parameters can be conveniently extracted in tabular form. Atm (lmfa) free-atom densities and related information, needed to start full-potential programs rst (lmf,binary) restart file, containing density and related information.

Together with the ctrl file, this file contains all information needed for a calculation rsta (lmf) same information as rst, but file is formatted, and therefore both portable across machines and amenable to editing. Eula (noncollinear package) holds a table of Euler angles.

Jr (lmgf) table of pairwise exchange interaction parameters qpts (lm,lmgf,lmpg,lmf) table of q-points, if user chooses to specify them. Hssn (lm,lmgf,lmpg,lmf) hessian matrix, containing densities of prior iterations, used for charge mixing in the self-consistency cycle. Gfqp (lmgf;binary) temporary file holding Green's functions for each q-point in the BZ at one energy. Used in branches where the GF over the entire zone is need at once, (e.g. Linear-response branches). For large systems or many k-points, this file can become extremely large. Psta (lm,lmgf) bare ASA response function for e-0, q-0.

See documentation file linear-response-asa.txt sigm (lm:sx) ASA self-energy, generated using sx branch vshft (lmgf,lmpg) a list of site potential shifts For a description of the generic structure of input files and its organization into categories and tokens, see The following is a typical example of the input file called `ctrl'; the description of each input token is documented in Each category in the sample below is displayed as hyperlink which points to the documentation for that category. LMASA-6 LM:7 ASA:7 Example of an ASA input file: Si with empty spheres You can put as many lines as you like.