Highly excited 1sns states of the helium atom

1976 ◽  
Vol 54 (10) ◽  
pp. 1543-1549 ◽  
Author(s):  
Mary Kuriyan ◽  
Huw O. Pritchard
Keyword(s):  
Wave Function ◽  
Helium Atom ◽  
Lower Energy ◽  
Computer Time ◽  
Suitable Choice ◽  
Triplet States ◽  
Astrophysical Interest ◽  
Variational Calculations ◽  
Singlet And Triplet States

Variational calculations are reported on the 1sns singlet and triplet states of the helium atom, up to and including n = 26. By suitable choice of terms in the expansion for the wave function, significant economies in computer time are possible, and we quote an example of a 12-term uncorrelated wave function which gives a lower energy than Pekeris' 220-term correlated wave function. The problems of extending these calculations to much higher n (e.g. n > 100) to include states of astrophysical interest are enumerated.

Lamb shift in the metastable states of the helium atom

1966 ◽  
Vol 291 (1424) ◽  
pp. 94-105 ◽  
Keyword(s):  
Helium Atom ◽  
Lamb Shift ◽  
Metastable States ◽  
Oscillator Strengths ◽  
Triplet States ◽  
Excitation Energies ◽  
Ionization Energies ◽  
Singlet And Triplet States ◽  
Experimental Values ◽  
Average Excitation Energy

The radiative corrections of order α 3 rydbergs are evaluated for the ionization energy of the metastable states 2 1 , 3 S, of the helium atom. In the calculation of the average excitation energy k 0 , the main contribution comes from the transition to and ( ms, np ) and ( ms, ∊p ) states. The oscillator strengths for transitions to (1 s, ∊p ), (2 s, ∊p ) and (3 s, ∊p ) states are evaluated by using six-parameter wavefunction for the metastable states and a product of a hydrogenic wavefunction with Z = 2 for the s electron and a wavefunction analogous to the Hartree wavefunction for the excited p electron. Making use of these oscillator strengths and a method used by Pekeris, the values of the average excitation energies for the singlet and triplet states are found to be 77.09 ± 1.6 and 79.84 ± 1.0 rydbergs respectively. With these values of the average excitation energies, the Lamb shift corrections, including the estimate of a α 4 Ry order corrections, to the ionization energies of the singlet and triplet states become – 0.106 ± 0.018 cm -1 and –0.129 ± 0.013 cm –1 respectively. When they are added to the theoretical values of the ionization energies obtained by Pekeris, the values of the ionization energies become 32033.212 ± 0.018 an d 38454.698 ± 0.013 cm -1 compared with Herzberg’s experimental values of 32033.24 ± 0.05 an d 38454.73 ± 0.05 cm -1 for the singlet and triplet states respectively.

The bounding energy for singlet and triplet states of the negative muonium ion

2011 ◽  
Vol 30 (0) ◽  
pp. 240-245 ◽  
Author(s):  
М. Гайсак ◽  
М. Гнатич ◽  
Ю. Федорняк
Keyword(s):  
Triplet States ◽  
Singlet And Triplet States

An ab initio study on some low-lying singlet and triplet states of SbO2+ and quartet states of SbO2

2006 ◽  
Vol 429 (4-6) ◽  
pp. 365-370 ◽  
Author(s):  
Edmond P.F. Lee ◽  
John M. Dyke ◽  
Foo-tim Chau ◽  
Wan-ki Chow ◽  
Daniel K.W. Mok
Keyword(s):  
Ab Initio ◽  
Triplet States ◽  
Ab Initio Study ◽  
Singlet And Triplet States

REDUCED MULTIREFERENCE COUPLED-CLUSTER METHOD AND ITS APPLICATION TO THE PYRIDYNE DIRADICALS

2008 ◽  
Vol 07 (04) ◽  
pp. 805-820 ◽  
Author(s):  
XIANGZHU LI ◽  
JOSEF PALDUS
Keyword(s):  
Molecular Geometry ◽  
External Source ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Triplet States ◽  
Correlation Effects ◽  
Spin Multiplicity ◽  
Triplet Splitting ◽  
Singlet And Triplet States

The reduced multireference (RMR) coupled-cluster (CC) method with singles and doubles (RMR CCSD) that employs a modest-size MR CISD wave function as an external source for the most important (primary) triples and quadruples in order to account for the nondynamic correlation effects in the presence of quasidegeneracy, and which is further perturbatively corrected for the remaining (secondary) triples, RMR CCSD(T), is employed to compute the molecular geometry and the energy of the lowest-lying singlet and triplet states, as well as the corresponding singlet–triplet splitting, for all possible isomers of the m, n-pyridyne diradicals. A comparison is made with earlier results that were obtained by other authors, and the role of the multireference effects for both the geometry and the spin multiplicity of the lowest state, as described by the RMR-type methods, is demonstrated on the example of 2,6- and 3,5-pyridynes.

The trion spin-singlet and -triplet states in ZnSe single quantum wells

2000 ◽  
Vol 214-215 ◽  
pp. 832-836 ◽  
Author(s):  
O Homburg ◽  
P Michler ◽  
K Sebald ◽  
J Gutowski ◽  
H Wenisch ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Triplet States ◽  
Single Quantum ◽  
Spin Singlet ◽  
Singlet And Triplet States
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