Changes and Improvements over Spartan'20

• Beginning with the Spartan'24 release, a host of Neural Network routines are available, replacing parts of calculations or in some cases full calculations previously performed with QM (density functional models). 
• Neural Networks are available / support the following standard Calculations: 
• Energy Corrected Density Functional Energies 
•  ωB97X-V/6-311+G(2df,2p)//ωB97X-D/6-31G*  
• ωB97M-V/6-311+G(2df,2p)//ωB97X-D/6-31G* 
• ωB97M(2)/6-311+G(2df,2p)//ωB97X-D/6-31G*
• Equilibrium Geometry Neutral Nets provide an Estimated Density Function ωB97X-D/6-31G* structure (additionally, energies from MMFF geometries are corrected estimating to ωB97X-V/6-311+G(2df,2p)//MMFF  
• Equilibrium Conformer the above five neural nets are available at multiple steps in the recipe.
• Conformer Distribution the above five neural nets are available at multiple steps in the recipe.
• NMR Spectrum the above five neural nets are available at multiple steps in the recipe, however the final NMR calculation (at present) still requires a single energy density functional calculation.
• Natural Products Database. The natural products with conformationally averaged calculated NMR spectra and experimental spectra (about 3,500 compounds and growing new literature.
• Spartan Spectra & Properties Database (SSPD). The Spartan Spectra & Properties Database (SSPD) collection has grown to >315,000+ entries (separate installation) - this has been extended to include an additional 8,000, predominantly drug and drug-like molecules and another 4,000 pesticide molecule. Entries have been combined affording thermodynamic data from the EDF2/6-31G* frequencies, reducing the overall memory footprint by perhaps 50%. A Transition State Database of more than 8,000 entries is included. These can be used in place of the existing library we presently utilize for transition state guessing, however, the major use is to generalize the Reactions Dialogue and provide application to activation energies (enthalpies, Gibbs energies) as well as overall reaction energies (enthalpies, Gibbs energies).
• Custom (user-generated) database formation. New in Spartan’24, a one-step save operation for “SSPD compatible” calculations. The minimum requirement is an ωB97X-D/6-31G* geometry. Optional are ωB97X-V/6-311+G(2df,2p) energies, EDF2/6-31G* frequencies and ωB97X-D/6-31G* chemical shifts. This also applies to transition states (absent the chemical shifts). The user entries can be automatically placed alongside the distributed SSPD.
• Expt. Data Menu. Experimental Chemical Shift input has been overhauled and is significantly easier with a new spreadsheet for organizing and inputting experimental data.
• Generate Isomers. Has been revised, primary utility is affording auto generated sets of stereoisomers for subsequent NMR calculations.
• 2D Drawings. The 2D rendering previously available as a tab from the Molecule Properties dialog has been replaced with a new Dual Display - providing 2D rendering when in 3D, and 3D visualization when working in the 2D sketch mode.
• Estimates tab. This new tab in the Molecule Properties dialog provides neural net estimates for energy, relative energy, Boltzmann wights and Cumulative Boltzmann weights, on the fly.
  speed increase as some data tables are calculated on-the-fly upon opening.
• Reactions Dialog has been expanded to accommodate reactants, transition states, and products, allowing for easy calculation of activation energies.
• Spartan’24 will take advantage of up to 16 cores for parallel jobs, with the option to license >16 cores as well (for high performance multi core systems), and includes our implementation of the Q-Chem version (roughly 5.4 at the time this list was compiled, a subsequent maintenance update will release our implementation of the new Q-Chem 6.0 later in 2024). 
• A new Check for Updates feature has been implemented in the Help menu. This won't force user's to update Spartan - but it will make the availability of  a newer version known, and supply the option to download it.