Gradient expansions for exchange-correlation functional at strong and weak limits similar in magnitude but opposite in sign, with generalized gradient approximations underestimating coefficient at strong coupling

https://pubmed.ncbi.nlm.nih.gov/38112505

The gradient expansions for the exchange-correlation functional at strong and weak interaction limits are similar in magnitude but have opposite signs, with generalized gradient approximations significantly underestimating the coefficient at strong coupling.