���q�������̃p�b�L���O�\�����t���O�����gMO�@(FMO)��p���āA�i�q�G�l���M�[�œK���@�Ōv�Z�����B���̋ߎ��@��p���邱�ƂŁA����Ȍ����\���̊i�q�G�l���M�[��Ab initio�̐��x��ۂ��Ȃ���AAb initio MO�@���g�p��������Z�����ԂŌv�Z���邱�Ƃ��”\�ł���B�Ód�|�e���V������_�d�׋ߎ����Ă���Ab initio�y�A�|�e���V�����@��p�����]���̌v�Z���ʂƔ�r���A�v�Z���@�̗L���������؂����B�܂��AFMO��p���邱�ƂŁA��͓I�ȃG�l���M�[�������s�����Ƃ��”\�Ȃ��߁Agradient��p�����G�l���M�[�œK���v�Z���s�����B�Ȃ��A�v�Z�ɗp�������q�ɂ‚��Ă͓������\����B

The packing structures of molecular crystals were calculated using the fragment MO(FMO) method. The results were compared with those from the ab initio pair potential method in which the electrostatic potential is approximated by the point charge interactions. Moreover, analytical energy gradient for the FMO method was incorporated into the computer program.