And the ground states for H_2COO, H(CH_3)COO, and (CH_3)_2COO are singlet (~1A), the ground states for HFCOO, and F_2COO are triplet (~3A). The cis forms of HFCOO and H (CH_3) COO are found to be more stable than the corresponding trans forms.

• H_2COO、H(CH_3)COO和(CH_3)_2COO的基态为单重态(~1A)；HFCOO和F_2COO的基态为三重态(~3A)；HFCOO和H(CH_3)COO的顺式结构比反式稳定.