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Simple perturbation and perturbation‐variation treatments of the 1 s σ g and 2 p σ u states of H 2 +
Author(s) -
Tung Eleanor W.,
Sanders William A.
Publication year - 1972
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560060414
Subject(s) - perturbation (astronomy) , wave function , atomic physics , perturbation theory (quantum mechanics) , zeroth law of thermodynamics , physics , chemistry , mathematical physics , quantum mechanics
First‐order wave functions and binding energies of the 1sσ g and 2pσ u states of H 2 +are calculated by simple methods for internuclear separations between 0.2 and 10 a 0 . An exact perturbation treatment of the lsσ g state with a zeroth‐order function of the form N exp (‐ sR λ/2) exp ( sR μ2) yields only fair results. An alternative method starts with zeroth‐order functions of the form N exp (‐ sR λ/2)[exp (‐ sR μ/2) ± exp ( sR μ/2)] for the 1 sσ gand 2 pσ ustates, respectively. An approximate first‐order trial function is set up and the energies are determined variationally. For both states the results are comparable to those obtained by exact perturbation treatments of the same order.