Magnetic susceptibility is a measure of how much a substance becomes magnetized when placed in an external magnetic field. In the case of a water molecule, we can calculate its magnetic susceptibility using quantum chemistry methods, such as ab initio calculations or density functional theory DFT .Here's a general outline of the steps to calculate the magnetic susceptibility of a water molecule using quantum chemistry methods:1. Choose a suitable quantum chemistry method: For this problem, we can use either ab initio calculations such as Hartree-Fock or Mller-Plesset perturbation theory or density functional theory DFT with an appropriate functional such as B3LYP or PBE .2. Select a basis set: A basis set is a collection of functions used to represent the molecular orbitals in the calculation. Common basis sets for water molecule calculations include 6-31G d,p and 6-311++G 2d,2p .3. Perform the electronic structure calculation: Using the chosen method and basis set, perform the electronic structure calculation for the water molecule. This will provide the molecular orbitals and their energies, as well as the total energy of the molecule.4. Calculate the magnetic susceptibility: The magnetic susceptibility can be calculated using the following formula: = -1/3 * _xx + _yy + _zz where _xx, _yy, and _zz are the diagonal elements of the polarizability tensor. These can be obtained from the electronic structure calculation by computing the response of the molecule to an external electric field in each of the x, y, and z directions.5. Analyze the results: The calculated magnetic susceptibility can be compared to experimental values or other theoretical calculations to assess the accuracy of the chosen method and basis set.Note that performing these calculations requires specialized software, such as Gaussian, ORCA, or Psi4, and a good understanding of quantum chemistry methods. The actual calculation process can be complex and computationally demanding, but following these general steps will guide you in calculating the magnetic susceptibility of a water molecule using quantum chemistry methods.