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| basis_input [2026/05/02 08:12] – [Basis blocks] werner | basis_input [2026/05/30 09:11] (current) – [Primitive set definition] werner |
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| In all four cases //type// defines the angular symmetry (''%%S, P, D, F, G, H,%%'' or ''I''). //type// can include several types, e.g., ''SPD'' or ''DF'' (this usually makes sense only with default library contractions or no contractions). The basis is loaded for all atoms with tag name //atom// in the geometry input. If //atom// is an integer, it refers to a z-matrix row. | In all four cases //type// defines the angular symmetry (''%%S, P, D, F, G, H,%%'' or ''I''). //type// can include several types, e.g., ''SPD'' or ''DF'' (this usually makes sense only with default library contractions or no contractions). The basis is loaded for all atoms with tag name //atom// in the geometry input. If //atom// is an integer, it refers to a z-matrix row. |
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| | If individual basis functions are specified, and "+" is given before the type (e.g. ''%%+S%%'', ''%%+P%%'') these functions are added to an existing default basis (only with molpro2026.1 or later). |
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| a) Library basis sets: | a) Library basis sets: |
| Load basis named //name// from the library. | Load basis named //name// from the library. |
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| If //scale// or //scale2// is present, all exponents are scaled by //scale// or //scale%%**%%2//, respectively. If //nprim// is specified, the first //nprim// exponents only are taken from the library. If //nprim// is negative or //ndel// is given, the last $|nprim|$ ($ndel$) basis functions from the library set are deleted. Associated with the library basis may be a set of default contraction coefficients which may be accessed in subsequent contraction cards. //type// can include several types, e.g., ''SPD'' or ''DF''. This usually makes sense only with default contractions, i.e., such cards should be followed only by “''%% C%%''” without any other specifications for contractions. | If ''SCALE'' or ''SCALE2'' is present, all exponents are scaled by //scale// or //scale%%**%%2//, respectively. If ''NPRIM'' is specified, the first //nprim// exponents only are taken from the library. If //nprim// is negative or ''DELETE=''//ndel// is given, the last $|nprim|$ ($ndel$) basis functions from the library set are deleted. In these cases only a single angular momentum (e.g. //s// or //p//) is allowed in //type//. Associated with the library basis may be a set of default contraction coefficients which may be accessed in subsequent contraction cards. //type// can include several types, e.g., ''SPD'' or ''DF''. This usually makes sense only with default contractions, i.e., such cards should be followed only by “''%% C%%''” without any other specifications for contractions. |
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| b) Explicit basis input: | b) Explicit basis input: |
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| The exponents (and other numerical parameters described below such as numbers of functions, and contraction coefficients) can be given as general input expressions, possibly involving variables. It is important to note, however, that these expressions are evaluated typically just once, at the same time as the complete basis set is parsed. This generally happens the first time that the basis set is required, perhaps before the first SCF calculation can be done. If the variables on which the basis depends are altered, this will not be noticed by the program, and the new basis set will not be used for subsequent stages of the computation. If, however, a new basis block is presented in the input, then the program marks as outdated any quantities such as integrals that have been calculated with the old basis set; subsequent job steps will then use the new basis. | The exponents (and other numerical parameters described below such as numbers of functions, and contraction coefficients) can be given as general input expressions, possibly involving variables. It is important to note, however, that these expressions are evaluated typically just once, at the same time as the complete basis set is parsed. This generally happens the first time that the basis set is required, perhaps before the first SCF calculation can be done. If the variables on which the basis depends are altered, this will not be noticed by the program, and the new basis set will not be used for subsequent stages of the computation. If, however, a new basis block is presented in the input, then the program marks as outdated any quantities such as integrals that have been calculated with the old basis set; subsequent job steps will then use the new basis. |
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| | If "+" is given before the type (e.g. +s, +p) these functions are added to a previously defined default basis. |
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| c) Even tempered basis sets: | c) Even tempered basis sets: |
| //type,atom//,''EVEN'',''NPRIM=''//nprim//,[''RATIO=''//ratio//],[''CENTRE=''//centre//],[''DRATIO=''//dratio//] | //type,atom//,''EVEN'',''NPRIM=''//nprim//,[''RATIO=''//ratio//],[''CENTRE=''//centre//],[''DRATIO=''//dratio//] |
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| Generates a generalized even tempered set of functions. The number of functions $n$ is specified by //nprim//, their geometric mean $c$ by //centre//, the mean ratio of successive exponents $r$ by //ratio//, and the variation of this ratio, $d$, by //dratio//. If //centre// is not given, the previous basis of the same type is extended by diffuse functions. If in this case //ratio// is not given, $r$ is determined from the exponents of the last two function of the previous basis. If this is not possible, the default $r=2.5$ is adopted. $d=1$ (the default) specifies a true even-tempered set, but otherwise the ratio between successive exponents changes linearly; the exponents are given explicitly by $$\log e_i = | Generates a generalized even tempered set of functions. The number of functions $n$ is specified by //nprim//, their geometric mean $c$ by //centre//, the mean ratio of successive exponents $r$ by //ratio//, and the variation of this ratio, $d$, by //dratio//. If //centre// is not given, the previous basis of the same type is extended by diffuse functions. This also holds if a default basis has been specified (only with molpro2026.1 or later). If in this case //ratio// is not given, $r$ is determined from the exponents of the last two function of the previous basis. If this is not possible, the default $r=2.5$ is adopted. $d=1$ (the default) specifies a true even-tempered set, but otherwise the ratio between successive exponents changes linearly; the exponents are given explicitly by $$\log e_i = |
| \log c | \log c |
| + ((n+1)/2-i) \,\log r | + ((n+1)/2-i) \,\log r |