The Energy Spectra of Soluble Potentials Within the Framework of the Variational Method

Authors

  • Ekwevugbe Omugbe
    Obafemi Awolowo University Ile-Ife
  • Etido P. Inyang
  • Clement A. Onate

Keywords:

variational method, Coulomb potential, Pseudoharmonic potential, Hulthen potential, Poschl-Teller-type potential

Abstract

In this article, we demonstrated the use of the variational approach in solving the bound state solutions of the Schrödinger equation for solvable potential functions. The method has been applied to determine the exact analytical excited states energy spectra for the Coulomb, and Pseudo-harmonic potentials. Also, the exact analytical ground state energy spectra for the Hulthén and Pöschl-Teller-type potentials have been obtained in closed form. In addition, we obtained the approximate energy eigenvalues of an exponential potential which does not admit exact analytical closed form solution. By minimizing the total variational energy, the variational parameters were derived. The results for these potential functions align perfectly with those obtained through other methods in the existing literature and numerical solution with the Matrix Numerov approach. The results demonstrate that the accuracy of the variational approach is strongly correlated with the use of accurate trial wave functions. 

Dimensions

Alzate-Cardona, J. D., Arbelaez-Echeverri, O.D. & Restrepo-Parra, E. (2017). Implementation details of a variational method to solve the time independent Schrödinger equation Revista Mexicana de Fisica E 63 12-20.

Amani, A.R. & Ghorbanpour, H. (2012). Supersymmetry Approach and Shape Invariance for Pseudo-Harmonic Potential. Acta Physica Polonica B 43, 1795-1804. https://doi.org/10.5506/APhysPolB.43.1795.

Bayrak O. & Boztosun I. (2007). Bound state solutions of the Hulthén potential by using the asymptotic iteration method. Phys. Scr. 76 92–96. http://doi.org/10.1088/0031-8949/76/1/016.

Cooper, F., Dawson, J. & Shepard, H. (1994). SUSY-based variational method for the anharmonic oscillator Phys, Lett. A 187, 140-144. https://doi.org/10.1016/0375-9601(94)90051-5.

Fernandez, F.M. (2011). Quantum Gaussian wells and barriers Ame. J. Phys. 79, 752-754. https://doi.org/10.1119/1.3574505

Filho, E.D. & Ricotta, R.M. (1995). Supersymmetry, Variational Method and Hulthén Potential. Mod. Phys. Lett. A. 10, 1613-1618. https://doi.org/10.1142/S0217732395001733.

Filho, E.D. & Ricotta, R.M. (2000). Morse potential energy spectra through the variational method and supersymmetry Phys. Lett. A 269, 269-276. https://doi.org/10.1016/S0375-9601(00)00267-X

Foulkes, W. M., Mitas, L., Needs, R. J., Rajagopal, G. (2001). Quantum Monte Carlo simulations of solids Rev. Mod. Phys. 73, 33-83. https://doi.org/10.1103/RevModPhys.73.33

Gaiki, P.M. and Gade, P.M. (2019). Using a variational method to obtain the ground state of the quantum Hamiltonian: symbolic computation approach. Eur. J. Phys. 40, 015806. https://doi.org/10.1088/1361-6404/aaf115.

Gning, M. T. , Sakho, I. , Faye, M. , Sow, M. , Diop, B. , Badiane, J. K. , Ba, D. & Diallo, A. (2021). Variational Calculations of Energies of the (2snl) 1,3Lπ and (2pnl) 1,3 Lπ Doubly Excited States in Two-Electron Systems Applying the Screening Constant per Unit Nuclear Charge. Journal of Modern Physics, 12, 328-352. https://doi.org/10.4236/jmp.2021.123024

Griffiths, D.J. (1995). Introduction to Quantum Mechanics. Prentice Hall Inc., Upper Saddle River , USA.

Hulthén, L. (1942). Uber die Eigenlösungen der Schrödinger chung des Deutrons. Ark. Mat. Astron. Fys. A. 28, 1–12

Ikhdair, S.M., Sever, R. (2008). Exact solution of the D-dimensional Schrodinger equation for a ringed-shaped Pseudo-harmonic potential. Cent. Eur. J. Phys. 6, 685-696. https://doi.org/10.2478/s11534-008-0024-2

Krynytskyi, Y & Rovenchak, A. (2021) Asymptotic Estimation for Eigenvalues in the Exponential Potential and for Zeros of K_iν (z) with Respect to Order. SIGMA; 17: 057. https://doi.org/10.3842/SIGMA.2021.057

Lucha, W. & Schöberl, F.F. (1999). Solving the Schrödinger equation for bound states with Mathematica 3.0. Int. J. Mod. Phys. C. 10, 607–619. https://doi.org/10.1142/S0129183199000450.

Maiz, F. (2020). Development and refinement of the Variational Method based on Polynomial Solutions of Schrödinger Equation Open Eng. 10, 415-423. https://doi.org/10.1515/eng-2020-0052.

Mutuk H. (2019). Asymptotic iteration and variational methods for Gaussian potential. Pramana J. Phys, 92, 66. https://doi.org/10.1007/s12043-019-1729-z.

Nikiforov, A. F.& Uvarov, V. B. V (1988). Special functions of mathematical physics Basel: Birkhäuser.

Omugbe, E., Aniezi, J. N., Ogundeji, S. O., Mbamara, C., Obodo, R. M., Njoku, I. J. &

Jahanshir, A. (2024). A new conjecture for obtaining the energy spectra of the wave

equations under solvable potentials. Quant. Stud. Math. Found. 11, 379-389. https://doi.org/10.1007/s40509-024-00327-6

Omugbe, E., Osafile, O. E., Enaibe, E. A., Onyeaju, M. C. & Akpata, E. (2021). Approximate non-relativistic s-wave energy spectra with nonpolynomial potentials within the framework of the WKB approximation Quant. Stud. Math. Found.8, 261-270. https://doi.org/10.1007/s40509-021-00244-y

Pillai, M., Goglio, J. & Walker, T. G. (2012). Matrix Numerov method for solving Schrödinger’s equation. Ame. J. Phys. 80:1017-1019. https://doi.org/10.1119/1.4748813

Rani, R., Bhardwaj, S.B. & Chand, F. (2008). Bound state solutions to the Schrödinger equation for some diatomic molecules Pramana, J. Physics. 91, 1-8. https://doi.org/10.1007/s12043-018-1622-1

Roussel, K. L. & Ocornell, R.F. (1974). Variational solution of Schroedinger's equation for the static screened Coulomb potential. Phy. Rev. A. 9, 52-56. https://doi.org/10.1103/PhysRevA.9.52

Szego, G. (1939). Orthogonal polynomials. American Math. Soc., Rhode Island, USA.

Tezcan, C. & Sever, R. (2009). A General Approach for the Exact Solution of the Schrödinger Equation Int. J. Theor. Phys. 48, 337-350. https://doi.org/10.1007/s10773-008-9806-y

Van der Vaart A., Le Phan S.T. & Wolfe B. (2025). Interactive Application and Visualization of the Variational Method to Aid Conceptual Understanding of Introductory Quantum Mechanics : J. Chem. Edu., 102, 2160−2166. https://doi.org/10.1021/acs.jchemed.4c01560

Zuniga J., Bastida A. & Requena A. (2012). Using the Screened Coulomb Potential To Illustrate the Variational Method J. Chem. Edu 89, 1152-1158. https://doi.org/10.1021/ed2003675

Published

2026-07-03

How to Cite

Omugbe, E., Inyang, E. P., & Onate, C. A. (2026). The Energy Spectra of Soluble Potentials Within the Framework of the Variational Method. Nigerian Journal of Physics, 35(4), 17-25. https://doi.org/10.62292/njp.v34i2.2025.569

How to Cite

Omugbe, E., Inyang, E. P., & Onate, C. A. (2026). The Energy Spectra of Soluble Potentials Within the Framework of the Variational Method. Nigerian Journal of Physics, 35(4), 17-25. https://doi.org/10.62292/njp.v34i2.2025.569