MOLPRO

11 BASIS INPUT 76
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
loge i = logc + ((n + 1)/2 − i) logr + 1 2 ((n + 1)/2 − i)2 logd
i = 1,2,...,n
Example 1
Example 2
SP,1,VTZ;C;SP,1,EVEN,1;
generates the generally contracted s and p triple-zeta basis sets
for atom 1 and extends these by one diffuse function.
SPD,1,VTZ,DELETE=1;C;
SP,1,EVEN,NPRIM=2,RATIO=2.5;
generates the generally contracted s, p triple-zeta basis sets for
atom 1. Two energy optimized d-functions of Dunning are included.
The last s and p functions are deleted and replaced by
two even tempered functions with ratio 2.5.
d) 3-term tempered basis sets:
type,atom,EVEN3,nprim,α, β, γ
Generates a 3-parameter set of nprim functions with exponents given by
e i = α;
e i = e i−1 β
(
γi 2 )
1 +
(nprim + 1) 2
e) Regular even tempered basis sets:
type,atom,EVENR,nprim,aa,ap,bb,bp
Generates an even tempered set of nprim functions according to the “regular” prescription described
in M W Schmidt and K Ruedenberg, J. Chem. Phys. 71 (1970) 3951. If any of the
parameters aa, ap, bb, bp is zero or omitted, the values are taken from table III of the above.
f) Even tempered basis set with confined progression:
type,atom,EVENP,nprim,α,β,γ
Generates an even tempered basis set with nprim functions and a maximal exponent given by α.
The progression (ratio) between the first and second exponent is adjusted using parameter β and
the progression between the last but one and the last exponent is adjusted with parameter γ. In
between the progression is linearly interpolated. The explicit values of the progression factors
are given by:
p(β) = exponenti
exponent i+1 = 5 π (arctan(β − 2.5) + π 2 ) + √ 2
so that for β ≪ 0 : p → √ 2 and for β ≫ 0 : p → 5 + √ 2 which limits the progression factors
in between these two values and enables unconstrained basis set optimisations. For β ≈ 0 the
progression has a factor of about 2.
type,atom,EVENP2,nprim,α,β,γ,δ
Generalises confined progression tempered basis sets by a third paramter (now γ) which defines
the progression as above in the centre. The ratio factors are then determined by interpolating
between p(β) → p(γ) and p(γ) → p(δ).