The digichem submit sub-module greatly simplifies the submission process for intermediate and advanced users, but for novice users the requirement to use the command-line and to write method files by hand is not ideal. For this scenario, the interactive submission interface is more suitable, which can be accessed using the digichem submit -I command (Figure ), or from the main menu. From this screen, the user can choose all the parameters of the calculation without using the command-line or generating the files manually. The starting geometries can be selected from a file-picker type interface (Figure ), similar to how files are selected in any commonly used GUI application, and the charge and multiplicity can be adjusted for each using text fields (Figure ). The empirical formula of each molecule is also displayed to permit the user to check that the correct structure has been loaded. Each selected starting geometry will start a separate calculation that will be run in parallel, the same as if submitting from the command-line. The calculation methods, meanwhile, can be selected from one of the approximately 240,000 pre-built calculations stored in Digichem's internal library, which cover the calculations of optimised geometries, vibrational frequencies, single-point energies and gradients, excited states, and NMR properties. This library is explored in a hierarchy (Figure and). The first level of the hierarchy corresponds to the chosen SLURM partition or PBS queue, and allows the user to pick, for example, between a high or low priority submission. The second level corresponds to the calculation submission engine. At present, Gaussian, Turbomole and Orca are all supported. The remaining levels select the specifics of the calculation itself, including the properties to be calculated (geometry optimisation, excited states, NMR properties, etc.), the computational method or functional, and the basis set. Multiple calculation methods can be chosen, and each will be performed in series, and the interface provides buttons to re-order the methods to ensure they are performed in the correct sequence. Each calculation method is associated with a unique numerical identifier (ID) consisting of three parts separated by a forward-slash, which in order correspond to: 1) the SLURM/PBS queue, 2) the calculation engine, and 3) the calculation itself. For example, the optimisation calculation shown in Figure has the unique code 1/4/182628. These calculation codes, if known in advance, can be used to quickly select a calculation from the internal library without navigating the interactive hierarchy, and can be specified on the command line to further speed up the submission process for advanced users. The library provides options for the most popular DFT functionals, including PBE0 and B3LYP, , as well as more advanced methods such as Møller-Plesset and coupledcluster theory, a variety of common solvents and the most common basis sets in the Pople, Karlsruhe, and correlation-consistent families. We expect that, in most cases, the Digichem library will provide all the calculation options that a novice computational chemist would require, but the interactive interface also provides options to load a method file in case the user wishes to write a method from scratch or re-use a method from a previous calculation. Finally, Digichem provides an interface to interactively modify the calculation options from any loaded method (Figure ). This interface groups related options together and provides help messages and validation, where appropriate, to help novice users find and understand each calculation option. In this way, a user could select an existing method from the library and modify it to suit their needs; for example, changing the basis set to one that is smaller and increasing the number of requested CPUs so that the calculation will run more quickly. Once the calculation has been set up to the user's specifications, all queued molecules will be submitted to the queuing manager simultaneously once the green 'confirm' button is pressed (Figure ).