SEARCH Articles Figures Tables Approximate Quantum Mechanical Calculation of Thermodynamic Properties Approximate methods of quantum mechanics Approximate techniques for alternative representations of quantum mechanics Approximation methods quantum-mechanical Computational quantum mechanics approximate orbital theories MNDO approximation, semiempirical quantum mechanics/molecular Oscillator approximation, quantum mechanical Quantum mechanics Born-Oppenheimer approximation Quantum mechanics methods approximation Quantum mechanics semiclassical approximation Quantum-mechanical treatment the first Born approximation Quantum-mechanical treatment the second Born approximation