# Supplementary Material (ESI) for Perkin Transactions # This journal is © The Royal Society of Chemistry 2002 data_global _journal_coden_Cambridge 188 _publ_requested_journal 'Perkin Transactions 2' loop_ _publ_author_name 'Almond, M. J.' 'Atkinson, Samantha D. M.' 'Bowmaker, G.' 'Drew, Michael G. B.' 'Feltham, Emma J.' 'Hollins, P.' 'Jenkins, Samantha L.' 'Wiltshire, K. S.' _publ_contact_author_name 'Dr M J Almond' _publ_contact_author_address ; Department of Chemistry University of Reading Whiteknights Reading RG6 6AD UK ; _publ_contact_author_email 'M.J.ALMOND@READING.AC.UK' _publ_section_title ; The Photodimerisation of the Chloro-, Methoxy-and Nitro-Derivatives of Trans-Cinnamic Acid: A Study of Single Crystalds by Vibrational Microspectroscopy. ; _publ_section_references ; Kabsch, W. (1988), J.Appl.Cryst 21 916-932. Sheldrick, G.M. (1990) SHELX86, Acta Cryst. A46 467-480. Sheldrick, G.M. (1993) SHELXL program for crystallography refinement. University of Gottingen, Germany. Spek, A.L., (1994) PLATON-94 program, Utrecht University, The Netherlands ; data_1 _database_code_CSD 186690 _audit_creation_method SHELXL-97 _chemical_name_systematic ; ? ; _chemical_name_common ? _chemical_formula_moiety ? _chemical_formula_sum 'C10 H10 O3' _chemical_formula_weight 178.18 loop_ _atom_type_symbol _atom_type_description _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag _atom_type_scat_source 'C' 'C' 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'H' 'H' 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'N' 'N' 0.0061 0.0033 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'O' 'O' 0.0106 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' _symmetry_cell_setting monoclinic _symmetry_space_group_name_H-M P21/a loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x+1/2, y+1/2, -z' '-x, -y, -z' 'x-1/2, -y-1/2, z' _cell_length_a 7.171(13) _cell_length_b 17.69(3) _cell_length_c 8.092(14) _cell_angle_alpha 90.00 _cell_angle_beta 117.774(10) _cell_angle_gamma 90.00 _cell_volume 908(3) _cell_formula_units_Z 4 _cell_measurement_temperature 293(2) _cell_measurement_reflns_used ? _cell_measurement_theta_min ? _cell_measurement_theta_max ? _exptl_crystal_description parallopiped _exptl_crystal_colour white _exptl_crystal_size_max 0.45 _exptl_crystal_size_mid 0.15 _exptl_crystal_size_min 0.15 _exptl_crystal_density_meas ? _exptl_crystal_density_diffrn 1.303 _exptl_crystal_density_method 'not measured' _exptl_crystal_F_000 376 _exptl_absorpt_coefficient_mu 0.096 _exptl_absorpt_correction_type none _exptl_absorpt_correction_T_min ? _exptl_absorpt_correction_T_max ? _exptl_special_details ; ? ; _diffrn_ambient_temperature 293(2) _diffrn_radiation_wavelength 0.71073 _diffrn_radiation_type MoK\a _diffrn_radiation_source 'fine-focus sealed tube' _diffrn_radiation_monochromator graphite _diffrn_measurement_device 'Marresearch Image Plate' _diffrn_measurement_method '95 frames at 2^o intervals, counting time 2 min.' _diffrn_detector_area_resol_mean ? _diffrn_standards_number ? _diffrn_standards_interval_count ? _diffrn_standards_interval_time ? _diffrn_standards_decay_% ? _diffrn_reflns_number 2778 _diffrn_reflns_av_R_equivalents 0.0913 _diffrn_reflns_av_sigmaI/netI 0.0887 _diffrn_reflns_limit_h_min 0 _diffrn_reflns_limit_h_max 8 _diffrn_reflns_limit_k_min -21 _diffrn_reflns_limit_k_max 21 _diffrn_reflns_limit_l_min -9 _diffrn_reflns_limit_l_max 8 _diffrn_reflns_theta_min 2.30 _diffrn_reflns_theta_max 26.09 _reflns_number_total 1680 _reflns_number_gt 751 _reflns_threshold_expression >2sigma(I) _computing_data_collection 'XDS (Kabsch, 1991)' _computing_cell_refinement XDS _computing_data_reduction XDS _computing_structure_solution 'SHELXS-86 (Sheldrick, 1990)' _computing_structure_refinement 'SHELXL-93 (Sheldrick, 1993)' _computing_molecular_graphics 'PLATON(Spek,1994)' _refine_special_details ; Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. ; _refine_ls_structure_factor_coef Fsqd _refine_ls_matrix_type full _refine_ls_weighting_scheme 'calc w=1/[\s^2^(Fo^2^)+(0.1576P)^2^+0.0000P] where P=(Fo^2^+2Fc^2^)/3' _atom_sites_solution_primary direct _atom_sites_solution_secondary difmap _atom_sites_solution_hydrogens geom _refine_ls_hydrogen_treatment mixed _refine_ls_extinction_method SHELXL _refine_ls_extinction_coef 0.049(17) _refine_ls_extinction_expression 'Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^' _refine_ls_number_reflns 1680 _refine_ls_number_parameters 121 _refine_ls_number_restraints 0 _refine_ls_R_factor_all 0.1824 _refine_ls_R_factor_gt 0.0840 _refine_ls_wR_factor_ref 0.2734 _refine_ls_wR_factor_gt 0.2252 _refine_ls_goodness_of_fit_ref 0.952 _refine_ls_restrained_S_all 0.952 _refine_ls_shift/su_max 0.000 _refine_ls_shift/su_mean 0.000 loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_adp_type _atom_site_occupancy _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group C1 C -0.3352(6) 0.3843(2) -0.2851(5) 0.0566(11) Uani 1 d . . . C2 C -0.4150(6) 0.3425(3) -0.1846(6) 0.0597(12) Uani 1 d . . . C3 C -0.6192(7) 0.3135(3) -0.2748(7) 0.0727(14) Uani 1 d . . . H3 H -0.6706 0.2843 -0.2094 0.087 Uiso 1 calc R . . C4 C -0.7454(7) 0.3287(3) -0.4638(7) 0.0836(16) Uani 1 d . . . H4 H -0.8824 0.3102 -0.5245 0.100 Uiso 1 calc R . . C5 C -0.6681(8) 0.3710(3) -0.5612(6) 0.0808(16) Uani 1 d . . . H5 H -0.7536 0.3817 -0.6868 0.097 Uiso 1 calc R . . C6 C -0.4670(7) 0.3971(3) -0.4736(6) 0.0666(13) Uani 1 d . . . H6 H -0.4159 0.4244 -0.5421 0.080 Uiso 1 calc R . . C11 C -0.1160(6) 0.4112(2) -0.1872(6) 0.0597(12) Uani 1 d . . . H11 H -0.0414 0.4004 -0.0603 0.072 Uiso 1 calc R . . C12 C -0.0139(6) 0.4491(3) -0.2609(6) 0.0631(12) Uani 1 d . . . H12 H -0.0829 0.4620 -0.3868 0.076 Uiso 1 calc R . . C13 C 0.2074(7) 0.4711(3) -0.1461(6) 0.0599(12) Uani 1 d . . . O14 O 0.3101(4) 0.45237(19) 0.0190(4) 0.0718(11) Uani 1 d . . . O15 O 0.2875(5) 0.5116(2) -0.2324(4) 0.0754(11) Uani 1 d . . . H15 H 0.4115 0.5208 -0.1608 0.090 Uiso 1 calc R . . O22 O -0.2816(4) 0.3317(2) 0.0014(4) 0.0759(11) Uani 1 d . . . C22 C -0.3575(8) 0.2922(4) 0.1120(7) 0.0918(18) Uani 1 d . . . H22A H -0.4778 0.3182 0.1065 0.110 Uiso 1 calc R . . H22B H -0.2485 0.2901 0.2392 0.110 Uiso 1 calc R . . H22C H -0.3972 0.2418 0.0648 0.110 Uiso 1 calc R . . loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_23 _atom_site_aniso_U_13 _atom_site_aniso_U_12 C1 0.055(2) 0.056(3) 0.061(2) -0.004(2) 0.0282(19) -0.001(2) C2 0.056(2) 0.060(3) 0.065(3) 0.001(2) 0.029(2) -0.001(2) C3 0.063(3) 0.067(3) 0.093(3) -0.004(3) 0.040(3) -0.014(2) C4 0.062(3) 0.093(4) 0.083(4) -0.023(3) 0.022(3) -0.017(3) C5 0.080(3) 0.096(4) 0.056(3) -0.005(3) 0.024(2) -0.008(3) C6 0.063(3) 0.071(3) 0.066(3) -0.008(2) 0.031(2) -0.005(2) C11 0.062(2) 0.061(3) 0.061(3) 0.003(2) 0.033(2) 0.001(2) C12 0.060(2) 0.073(3) 0.055(2) 0.005(2) 0.026(2) -0.007(2) C13 0.070(3) 0.058(3) 0.065(3) 0.000(2) 0.041(2) -0.005(2) O14 0.0636(18) 0.092(3) 0.0614(19) 0.0133(17) 0.0306(16) -0.0082(16) O15 0.0638(19) 0.095(3) 0.0670(19) 0.0052(17) 0.0305(15) -0.0179(18) O22 0.0616(17) 0.095(3) 0.071(2) 0.0219(18) 0.0310(15) -0.0073(17) C22 0.084(3) 0.108(5) 0.089(4) 0.033(3) 0.044(3) -0.007(3) _geom_special_details ; All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. ; loop_ _geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 _geom_bond_distance _geom_bond_site_symmetry_2 _geom_bond_publ_flag C1 C6 1.389(6) . ? C1 C2 1.403(6) . ? C1 C11 1.472(6) . ? C2 O22 1.369(5) . ? C2 C3 1.394(6) . ? C3 C4 1.393(7) . ? C4 C5 1.376(7) . ? C5 C6 1.357(7) . ? C11 C12 1.321(6) . ? C12 C13 1.469(7) . ? C13 O14 1.233(5) . ? C13 O15 1.306(5) . ? O22 C22 1.428(5) . ? loop_ _geom_angle_atom_site_label_1 _geom_angle_atom_site_label_2 _geom_angle_atom_site_label_3 _geom_angle _geom_angle_site_symmetry_1 _geom_angle_site_symmetry_3 _geom_angle_publ_flag C6 C1 C2 118.0(4) . . ? C6 C1 C11 123.2(4) . . ? C2 C1 C11 118.7(4) . . ? O22 C2 C3 123.3(4) . . ? O22 C2 C1 116.5(4) . . ? C3 C2 C1 120.2(4) . . ? C4 C3 C2 119.3(4) . . ? C5 C4 C3 120.3(4) . . ? C6 C5 C4 120.0(4) . . ? C5 C6 C1 122.1(4) . . ? C12 C11 C1 126.8(4) . . ? C11 C12 C13 120.8(4) . . ? O14 C13 O15 122.5(4) . . ? O14 C13 C12 122.5(4) . . ? O15 C13 C12 115.0(4) . . ? C2 O22 C22 118.8(3) . . ? _refine_diff_density_max 0.304 _refine_diff_density_min -0.223 _refine_diff_density_rms 0.069 #===END data_2 _database_code_CSD 186691 _audit_creation_method SHELXL-97 _chemical_name_systematic ; ? ; _chemical_name_common ? _chemical_formula_moiety ? _chemical_formula_sum 'C10 H10 O3' _chemical_formula_weight 178.18 loop_ _atom_type_symbol _atom_type_description _atom_type_scat_dispersion_real _atom_type_scat_dispersion_imag _atom_type_scat_source 'C' 'C' 0.0033 0.0016 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'H' 'H' 0.0000 0.0000 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'N' 'N' 0.0061 0.0033 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' 'O' 'O' 0.0106 0.0060 'International Tables Vol C Tables 4.2.6.8 and 6.1.1.4' _symmetry_cell_setting monoclinic _symmetry_space_group_name_H-M P21/n loop_ _symmetry_equiv_pos_as_xyz 'x, y, z' '-x+1/2, y+1/2, -z+1/2' '-x, -y, -z' 'x-1/2, -y-1/2, z-1/2' _cell_length_a 8.655(12) _cell_length_b 4.919(7) _cell_length_c 21.97(2) _cell_angle_alpha 90.00 _cell_angle_beta 97.860(10) _cell_angle_gamma 90.00 _cell_volume 927(2) _cell_formula_units_Z 4 _cell_measurement_temperature 293(2) _cell_measurement_reflns_used ? _cell_measurement_theta_min ? _cell_measurement_theta_max ? _exptl_crystal_description parallelopiped _exptl_crystal_colour white _exptl_crystal_size_max 0.25 _exptl_crystal_size_mid 0.25 _exptl_crystal_size_min 0.20 _exptl_crystal_density_meas ? _exptl_crystal_density_diffrn 1.277 _exptl_crystal_density_method 'not measured' _exptl_crystal_F_000 376 _exptl_absorpt_coefficient_mu 0.094 _exptl_absorpt_correction_type none _exptl_absorpt_correction_T_min ? _exptl_absorpt_correction_T_max ? _exptl_special_details ; ? ; _diffrn_ambient_temperature 293(2) _diffrn_radiation_wavelength 0.71069 _diffrn_radiation_type MoK\a _diffrn_radiation_source 'fine-focus sealed tube' _diffrn_radiation_monochromator graphite _diffrn_measurement_device 'Marresearch Image Plate' _diffrn_measurement_method '95 frames at 2^o intervals, counting time 2 min.' _diffrn_detector_area_resol_mean ? _diffrn_standards_number ? _diffrn_standards_interval_count ? _diffrn_standards_interval_time ? _diffrn_standards_decay_% ? _diffrn_reflns_number 5343 _diffrn_reflns_av_R_equivalents 0.0561 _diffrn_reflns_av_sigmaI/netI 0.0622 _diffrn_reflns_limit_h_min -10 _diffrn_reflns_limit_h_max 10 _diffrn_reflns_limit_k_min -5 _diffrn_reflns_limit_k_max 5 _diffrn_reflns_limit_l_min -26 _diffrn_reflns_limit_l_max 26 _diffrn_reflns_theta_min 3.74 _diffrn_reflns_theta_max 25.92 _reflns_number_total 1720 _reflns_number_gt 1340 _reflns_threshold_expression >2sigma(I) _computing_data_collection 'XDS (Kabsch, 1991)' _computing_cell_refinement XDS _computing_data_reduction XDS _computing_structure_solution 'SHELXS-86 (Sheldrick, 1990)' _computing_structure_refinement 'SHELXL-93 (Sheldrick, 1993)' _computing_molecular_graphics 'PLATON(Spek,1994)' _refine_special_details ; Refinement of F^2^ against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F^2^, conventional R-factors R are based on F, with F set to zero for negative F^2^. The threshold expression of F^2^ > 2sigma(F^2^) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F^2^ are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. ; _refine_ls_structure_factor_coef Fsqd _refine_ls_matrix_type full _refine_ls_weighting_scheme 'calc w=1/[\s^2^(Fo^2^)+(0.1296P)^2^+0.1236P] where P=(Fo^2^+2Fc^2^)/3' _atom_sites_solution_primary direct _atom_sites_solution_secondary difmap _atom_sites_solution_hydrogens geom _refine_ls_hydrogen_treatment mixed _refine_ls_extinction_method SHELXL _refine_ls_extinction_coef 0.04(2) _refine_ls_extinction_expression 'Fc^*^=kFc[1+0.001xFc^2^\l^3^/sin(2\q)]^-1/4^' _refine_ls_number_reflns 1720 _refine_ls_number_parameters 121 _refine_ls_number_restraints 0 _refine_ls_R_factor_all 0.0871 _refine_ls_R_factor_gt 0.0693 _refine_ls_wR_factor_ref 0.2285 _refine_ls_wR_factor_gt 0.2064 _refine_ls_goodness_of_fit_ref 1.118 _refine_ls_restrained_S_all 1.118 _refine_ls_shift/su_max 0.209 _refine_ls_shift/su_mean 0.014 loop_ _atom_site_label _atom_site_type_symbol _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_U_iso_or_equiv _atom_site_adp_type _atom_site_occupancy _atom_site_calc_flag _atom_site_refinement_flags _atom_site_disorder_assembly _atom_site_disorder_group C1 C 0.3973(3) 1.2041(5) 0.31942(13) 0.0657(7) Uani 1 d . . . H1 H 0.3362 1.3361 0.2974 0.079 Uiso 1 calc R . . C2 C 0.5159(3) 1.0747(5) 0.29387(12) 0.0627(7) Uani 1 d . . . C3 C 0.6064(3) 0.8786(5) 0.32718(11) 0.0606(7) Uani 1 d . . . H3 H 0.6855 0.7927 0.3098 0.073 Uiso 1 calc R . . C4 C 0.5804(3) 0.8086(5) 0.38644(11) 0.0560(7) Uani 1 d . . . C5 C 0.4600(3) 0.9375(5) 0.41146(12) 0.0638(7) Uani 1 d . . . H5 H 0.4397 0.8910 0.4506 0.077 Uiso 1 calc R . . C6 C 0.3712(3) 1.1331(6) 0.37840(13) 0.0706(8) Uani 1 d . . . H6 H 0.2924 1.2195 0.3958 0.085 Uiso 1 calc R . . O31 O 0.5515(3) 1.1269(5) 0.23618(9) 0.0945(8) Uani 1 d . . . C32 C 0.4563(5) 1.3173(8) 0.19951(16) 0.1086(14) Uani 1 d . . . H32A H 0.3523 1.2467 0.1904 0.130 Uiso 1 calc R . . H32B H 0.4983 1.3481 0.1619 0.130 Uiso 1 calc R . . H32C H 0.4540 1.4857 0.2215 0.130 Uiso 1 calc R . . C41 C 0.6765(3) 0.6061(5) 0.42396(11) 0.0606(7) Uani 1 d . . . H41 H 0.6542 0.5804 0.4638 0.073 Uiso 1 calc R . . C42 C 0.7894(3) 0.4590(5) 0.40749(11) 0.0615(7) Uani 1 d . . . H42 H 0.8133 0.4785 0.3677 0.074 Uiso 1 calc R . . C43 C 0.8809(3) 0.2641(5) 0.44858(11) 0.0577(7) Uani 1 d . . . O44 O 0.8429(3) 0.2261(4) 0.50219(8) 0.0779(7) Uani 1 d . . . H44 H 0.9156 0.1540 0.5242 0.093 Uiso 1 calc R . . O45 O 0.9914(2) 0.1410(4) 0.42947(8) 0.0721(7) Uani 1 d . . . loop_ _atom_site_aniso_label _atom_site_aniso_U_11 _atom_site_aniso_U_22 _atom_site_aniso_U_33 _atom_site_aniso_U_23 _atom_site_aniso_U_13 _atom_site_aniso_U_12 C1 0.0569(15) 0.0596(15) 0.0801(17) 0.0053(12) 0.0080(12) 0.0054(11) C2 0.0594(14) 0.0631(15) 0.0667(15) 0.0101(11) 0.0131(11) 0.0009(11) C3 0.0542(15) 0.0626(15) 0.0667(15) 0.0070(11) 0.0142(11) 0.0066(10) C4 0.0607(15) 0.0514(13) 0.0551(13) 0.0015(10) 0.0052(10) -0.0081(10) C5 0.0645(16) 0.0682(16) 0.0597(14) -0.0031(11) 0.0124(11) -0.0089(11) C6 0.0598(16) 0.0765(17) 0.0779(18) -0.0105(13) 0.0180(13) 0.0024(12) O31 0.0953(16) 0.1159(18) 0.0780(13) 0.0433(12) 0.0326(11) 0.0407(13) C32 0.113(3) 0.125(3) 0.091(2) 0.051(2) 0.024(2) 0.042(2) C41 0.0653(15) 0.0602(15) 0.0561(13) 0.0012(10) 0.0071(11) -0.0091(11) C42 0.0725(16) 0.0615(14) 0.0512(13) 0.0034(10) 0.0112(11) -0.0040(12) C43 0.0681(16) 0.0548(14) 0.0492(13) 0.0019(9) 0.0048(11) -0.0073(11) O44 0.0839(15) 0.0897(15) 0.0621(12) 0.0146(9) 0.0173(10) 0.0207(11) O45 0.0826(14) 0.0788(13) 0.0564(11) 0.0099(8) 0.0151(9) 0.0132(10) _geom_special_details ; All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. ; loop_ _geom_bond_atom_site_label_1 _geom_bond_atom_site_label_2 _geom_bond_distance _geom_bond_site_symmetry_2 _geom_bond_publ_flag C1 C6 1.390(4) . ? C1 C2 1.390(4) . ? C2 O31 1.369(3) . ? C2 C3 1.386(4) . ? C3 C4 1.394(4) . ? C4 C5 1.395(4) . ? C4 C41 1.475(4) . ? C5 C6 1.375(4) . ? O31 C32 1.423(4) . ? C41 C42 1.307(4) . ? C42 C43 1.472(3) . ? C43 O45 1.252(3) . ? C43 O44 1.279(3) . ? loop_ _geom_angle_atom_site_label_1 _geom_angle_atom_site_label_2 _geom_angle_atom_site_label_3 _geom_angle _geom_angle_site_symmetry_1 _geom_angle_site_symmetry_3 _geom_angle_publ_flag C6 C1 C2 119.0(2) . . ? O31 C2 C3 115.9(2) . . ? O31 C2 C1 124.0(2) . . ? C3 C2 C1 120.0(3) . . ? C2 C3 C4 120.9(2) . . ? C3 C4 C5 118.7(2) . . ? C3 C4 C41 122.5(2) . . ? C5 C4 C41 118.8(2) . . ? C6 C5 C4 120.2(2) . . ? C5 C6 C1 121.2(2) . . ? C2 O31 C32 117.5(2) . . ? C42 C41 C4 127.2(2) . . ? C41 C42 C43 123.4(2) . . ? O45 C43 O44 122.9(2) . . ? O45 C43 C42 118.7(2) . . ? O44 C43 C42 118.4(2) . . ? _refine_diff_density_max 0.303 _refine_diff_density_min -0.213 _refine_diff_density_rms 0.050