As a language model AI, I cannot perform actual calculations or simulations. However, I can provide you with a general understanding of how to approach this problem using time-dependent density functional theory TD-DFT .To determine the electronic structure and composition of the first excited state of the ethylene molecule C2H4 using TD-DFT, you would need to follow these steps:1. Choose an appropriate functional and basis set: Select a suitable exchange-correlation functional e.g., B3LYP, PBE, etc. and a basis set e.g., 6-31G, cc-pVDZ, etc. for your calculations. The choice of functional and basis set can significantly affect the accuracy of your results, so it is essential to choose wisely based on the literature or previous studies.2. Perform a ground-state DFT calculation: First, you need to optimize the geometry of the ethylene molecule in its ground state using DFT. This will provide you with the optimized molecular structure and the ground-state electronic configuration.3. Perform a TD-DFT calculation: Once you have the optimized ground-state structure, you can perform a TD-DFT calculation to obtain the excited-state energies and transition properties. This calculation will provide you with information about the first excited state, including its energy, electron configuration, and the nature of the electronic transition e.g., to * or n to * .4. Analyze the results: After obtaining the excited-state information, you can analyze the results to understand the electronic structure and composition of the first excited state. This may involve visualizing the molecular orbitals involved in the transition, calculating the oscillator strength, and examining the electron density difference between the ground and excited states.Remember that the accuracy of the results depends on the chosen functional and basis set, as well as the quality of the software used for the calculations. It is always a good idea to compare your results with experimental data or other theoretical methods to ensure their reliability.