Predicting catalysis: understanding ammonia synthesis from first-principles calculations. by Hellman, A, Baerends, E, Biczysko, M, Bligaard, T, Christensen, C, Clary, D, Dahl, S, van Harrevelt, R, Honkala, K, Jonsson, H, Kroes, G, Luppi, M, Manthe, U, Nørskov, J, Olsen, R, Rossmeisl, J, Skúlason, E, Tautermann, C, Varandas, A, Vincent, J