Hi all,

This is Cheng, I am working on EDA analysis (unrestricted calculation) on a diradical transition state via Q-Chem.

But I have a hard time for getting a diradical nature of the transition state in my calculation. In more detail, I am studying the chemical process: two close-shell singlet species react with each other to generate two doublet radical products. The transition state has been proved a diradical species. Now I am working on EDA analysis on this diradical transition state, where two fragments are two close-shell singlets (i.e. reactant-like). All my calculation were actually close-shell (i.e S^2 =0 or very close to 0). I wonder if is there any way to ensure the EDA can capture the diradical nature of the transition state?

An example input file. Feel free to let me know whether I made a mistake here.

$>Lgm}bo:E\molecule 0 1 --- 0 1 ***** ***** ***** --- 0 1 ***** ***** *****$>Lgm}bo:E\end

$>Lgm}bo:E\rem JOBTYPE EDA EDA2 1 METHOD wb97xd BASIS def2-TZVP FRGM_METHOD GIA FRGM_LPCORR RS_EXACT_SCF EDA_BSSE TRUE ITHRSH 12 MEM_TOTAL 4000 MEM_STATIC 2000 SCF_PRINT_FRGM 1 MAX_SCF_CYCLES 300 UNRESTRICTED True SCF_GUESS_MIX 5 INTERNAL_STABILITY True INTERNAL_STABILITY_ITER 5 INTERNAL_STABILITY_DAVIDSON_ITER 100$>Lgm}bo:E\end

Thanks,
Cheng