Claim Missing Document
Check
Articles

Found 4 Documents
Search

PENDEKATAN FUNGSI BASIS SATU DIMENSI UNTUK MENYELESAIKAN PERSAMAAN SCHRÖDINGER UNTUK SISTEM ATOM DAN MOLEKUL MULTI-ELEKTRON Sarwono, Yanoar Pribadi
PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) Vol. 12 (2024): PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) SNF2023
Publisher : Program Studi Pendidikan Fisika dan Program Studi Fisika Universitas Negeri Jakarta, LPPM Universitas Negeri Jakarta, HFI Jakarta, HFI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/03.1201.FA16

Abstract

Abstrak Belakangan ini, kami berhasil menyelesaikan persamaan Schrödinger untuk atom multi-elektron dengan menggunakan pendekatan kombinasi linier fungsi basis satu dimensi. Implementasi fungsi basis satu dimensi memungkinkan pemisahan masalah atom menjadi komponen Cartesiannya, tidak seperti metode struktur elektronik standar yang melakukan pemisahan atas partikel. Matriks Hamiltonian dari seluruh elektron yang bersifat sparse dihasilkan dengan metode finite-difference dan pada orde standar. Kemudian sistem satu dimensi terkait dijadikan sebagai fungsi gelombang percobaan. Hasil yang didapat disempurnakan lebih lanjut dengan residual vector correction. Sebagai hasil, energi total yang diperoleh bersifat konvergen dan stabil. Total energi yang diperoleh juga akurat hingga angka desimal kelima. Selain itu, proses yang berlangsung merupakan proses variational yang berasal dari batas atas hasil dari fungsi gelombang percobaan. Dengan metode ini, banyak permasalahan, terutama yang berkaitan dengan proses evaluasi elemen matriks Hamiltonian dapat diatasi. Sebagai contoh, potensial dengan multi-center yang terdapat pada kasus molekul dapat dievaluasi dengan integrasi numerik multi-dimensi yang berlangsung dengan mudah, tanpa memerlukan pembagian sistem molekul menjadi beberapa molekul dengan pusat tunggal serta tanpa perlu dilakukan transformasi Fourier. Dibandingkan dengan pendekatan standar single-electron, solusi yang diperoleh dapat memperhitungan secara akurat efek many-body atau electron correlation yang dapat ditemukan dalam energi tolakan elektron-elektron. Terlebih, fungsi gelombang Schrödinger yang dihasilkan berisi informasi yang komprehensif yang dapat digunakan untuk melakukan plot radial correlation dan fungsi distribusi. Kata-kata kunci: Persamaan Schrödinger, helium, molekul hidrogen, residual vector correction. Abstract Recently we solved the Schrödinger equation for multi-electron atoms with the use of a linear combination of one-dimensional basis functions. The implementation of the one-dimensional basis functions allows the separation of the atomic problems into their Cartesian components, unlike the standard electronic structure methods of particle-separability. The all-electron sparse Hamiltonian matrix is generated with the standard order finite-difference method, and the corresponding one-dimensional systems become the trial wave function, continued with the refinement of the results using the residual vector correction. The converged and stable energy up to five decimal places is obtained variationally from a strictly upper bound one. Many problems associated with the evaluation matrix elements of the Hamiltonian particularly the multi-center potentials present in the molecular cases are circumvented due to the easy multi-dimensional numerical integration without any partitions of molecular systems into single-center terms and any Fourier transform. Distinctive from the standard single-electron approach, the obtained solution treats more accurately many-body effect of electron correlation found in the electron-electron repulsion energy. Furthermore, the obtained Schrödinger wave function contains vast information sufficient for the radial correlation and distribution function. Keywords: Schrödinger equation, helium, hydrogen molecule, residual vector correction, electron correlations.
SOLUSI PERSAMAAN SCHRÖDINGER UNTUK MOLEKUL DIATOMIK SEDERHANA MENGGUNAKAN FUNGSI GELOMBANG SATU PARAMETER SLATER-TYPE ORBITAL Riyanto, Fiqri Aditya; Prayitno, Teguh Budi; Sarwono, Yanoar Pribadi
PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) Vol. 12 (2024): PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) SNF2023
Publisher : Program Studi Pendidikan Fisika dan Program Studi Fisika Universitas Negeri Jakarta, LPPM Universitas Negeri Jakarta, HFI Jakarta, HFI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/03.1201.FA37

Abstract

Abstrak Dalam paper ini kami menyajikan solusi persamaan Schrödinger untuk molekul diatomik sederhana menggunakan fungsi gelombang satu parameter Slater-type orbital. Fungsi gelombang disusun dengan pendekatan orbital molekul, dan dilanjutkan dengan optimasi eksponen orbital. Kami mengevaluasi 128 suku integral orbital molekul secara analitik untuk memperoleh energi total, dan kami menyajikan kurva energi potensial untuk bonding configuration dan menganalisis bagaimana proses disosiasi kedua atom. Hasil kami mendekati dengan perhitungan yang akurat dan menunjukkan peningkatan dari perhitungan standar. Kami juga membandingkan penggunaan Slater-type orbital dan Gaussian-type orbital serta perilakunya terhadap fungsi orbital 1s. Kata-kata kunci: Persamaan Schrödinger, Slater-Type Orbital, Pendekatan MO, Solusi analitik. Abstract In this paper we present the solution of Schrödinger equation for simple diatomic molecules using the one-parameter Slater-type orbitals wave function. The wave function is constructed with the molecular orbital approach, and continued by orbital exponent optimization. We evaluating 128 molecular orbital integral terms analytically to obtain total energy, and we serve the potential energy curves for the bonding configuration and analyze how the dissociation process of two atoms. Our results are in good agreement with the accurate calculations and show good improvement than the standard calculations. We also compare the use of Slater-type and Gaussian-type orbitals and its behavior to the 1s orbital functions. Keywords: Schrödinger equation, Slater-Type Orbital, MO approaches, Analytical solution.
PENDEKATAN DEEP LEARNING UNTUK MEMPREDIKSI ENERGI KEADAAN DASAR BERDASARKAN POTENSIAL OSILATOR HARMONIK SEDERHANA DUA DIMENSI Jaelani, Achmad; Prayitno, Teguh Budi; Sarwono, Yanoar Pribadi
PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) Vol. 12 (2024): PROSIDING SEMINAR NASIONAL FISIKA (E-JOURNAL) SNF2023
Publisher : Program Studi Pendidikan Fisika dan Program Studi Fisika Universitas Negeri Jakarta, LPPM Universitas Negeri Jakarta, HFI Jakarta, HFI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/03.1201.FA38

Abstract

Abstrak Penelitian ini mengusulkan pendekatan deep learning untuk memprediksi energi keadaan dasar elektron berdasarkan potensial osilator harmonik sederhana dua dimensi dari persamaan Schrödinger. Metode ini menggunakan jaringan saraf konvolusi untuk mempelajari hubungan antara potensial dan energi keadaan dasar. Dataset osilator harmonik sederhana dihasilkan dengan fungsi skalar dimana parameter-parameter dihasilkan secara acak. Kinerja pendekatan yang diusulkan dibandingkan dengan metode numerik, seperti metode beda hingga. Hasil yang diperoleh menunjukkan bahwa pendekatan deep learning lebih efisien dan akurat dalam memprediksi energi keadaan dasar berdasarkan potensial osilator harmonik sederhana dua dimensi. Model mendapatkan mean squared error sebesar 6.37×10-7 mHa pada data uji. Pendekatan ini memiliki potensi aplikasi dalam berbagai bidang, seperti ilmu material, komputasi kimia, dan mekanika kuantum. Kata-kata kunci: Deep Learning, Persamaan Schrödinger, Energi Keadaan Dasar. Abstract This research proposes a deep learning approach to predict the ground state energy of an electron based on the two-dimensional simple harmonic oscillator potential of the Schrödinger equation. The approach uses convolutional neural networks to learn the relationship between the potential and the ground state energy. The simple harmonic oscillator dataset is generated with a scalar function where the parameters are randomly generated. The performance of the proposed approach is compared with numerical methods, such as the finite difference methods. The results show that the deep learning approach is more efficient and accurate in predicting the ground state energy based on the two-dimensional simple harmonic oscillator potential, achieving a mean squared error of 6.37×10-7 mHa on the test data. This remarkable performance demonstrates the potential of the proposed approach for applications in various fields, including material science and quantum mechanics. Keywords: Deep Learning, Schrödinger Equation, Ground State Energy.
Application of Variational Quantum Eigensolver for Ground State Energies Calculation in Hydrogen and Helium Atomic Sequences Hakim, Difa Farhani; Prayitno, Teguh Budi; Sarwono, Yanoar Pribadi
Spektra: Jurnal Fisika dan Aplikasinya Vol. 9 No. 3 (2024): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 9 Issue 3, December 2024
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.093.03

Abstract

Exponential scaling presents a significant challenge in electronic structure calculations performed on classical computers. This paper explores how quantum computer algorithms can accurately represent quantum systems. Variational Quantum Eigensolver (VQE) algorithm is used to compute the ground state energy of hydrogen and helium sequences by implementing variational principle and quantum gates as trial wavefunction. This technique combines classical optimization with quantum computing calculations to simulate quantum systems on noisy and resource-limited computers. The resulting calculated energy is highly consistent to the corresponding exact values and Hartree-Fock calculations with a trend of when the number of atoms increases the calculated energy becomes more negative, leading to a decrease in the percentage error. Moreover, the convergence of the ground state energy of hydrogen and helium atoms was effectively optimized. The desired energy was reached, proven by adjusting the expectation value, and gradually achieving unity in state overlap. These findings demonstrate the VQE method's accuracy in calculating simple quantum systems and its scalability for larger atomic and molecular system, such as those in quantum chemistry and material science. However, challenges in quantum computer simulations, such as limited in qubit numbers and the presence of noise, require further advancements. Therefore, implementing a larger basis sets, advanced qubit mapping, specific chemistry ansatz, and flexible optimization techniques is one way to improve overall calculation.