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18. More Special Functions. Hermite Functions Applications of Hermite Functions Laguerre Functions Chebyshev Polynomials Hypergeometric Functions Confluent Hypergeometric Functions Dilogarithm Elliptic Integrals. 1. Hermite Functions. Hermite ODE :. Hermite functions
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18. More Special Functions Hermite Functions Applications of Hermite Functions Laguerre Functions Chebyshev Polynomials Hypergeometric Functions Confluent Hypergeometric Functions Dilogarithm Elliptic Integrals
1. Hermite Functions Hermite ODE : Hermite functions Hermite polynomials ( n = integer ) Hermitian form Rodrigues formula Assumed starting point here. Generating function :
Recurrence Relations All Hncan be generated by recursion.
Table & Fig. 18.1. Hermite Polynomials Mathematica
Special Values
Hermite ODE Hermite ODE
Rodrigues Formula Rodrigues Formula
Series Expansion consistent only if n is even For n odd, j & k can run only up to m1, hence &
Orthogonality & Normalization Orthogonal Let
2. Applications of Hermite Functions Simple Harmonic Oscillator (SHO) : Let Set
Eq.18.19 is erronous
Fig.18.2. n Mathematica
Operator Appoach see § 5.3 Factorize H : Let
Set or
c = const with i.e., a is a lowering operator i.e., a+ is a raising operator with
Since we have ground state Set m = 0 with ground state Excitation = quantum / quasiparticle : a+ a = number operator a+ = creation operator a = annihilation operator
Molecular Vibrations For molecules or solids : For molecules : For solids : R = positions of nuclei r = positions of electron Born-Oppenheimer approximation : R treated as parameters Harmonic approximation : Hvibquadratic in R. Transformation to normal coordinatesHvib = sum of SHOs. Properties, e.g., transition probabilities require m = 3, 4
Example 18.2.1. Threefold Hermite Formula for Triangle condition i,j,k= cyclic permuation of 1,2,3 for
Consider
Hermite Product Formula Set Range of set by q! q 0
Mathematica
Example 18.2.2.Fourfold Hermite Formula Mathematica
Product Formula with Weight exp(a2 x2) Ref: Gradshteyn & Ryzhik, p.803